build.zig: incorrect handling of the ziglings logo

[perillo]

In build.zig, the logo is print unconditionally to stderr. This causes the logo to be printed twice, when listing all the available steps.

$ zig build -l

         _       _ _
     ___(_) __ _| (_)_ __   __ _ ___
    |_  | |/ _' | | | '_ \ / _' / __|
     / /| | (_| | | | | | | (_| \__ \
    /___|_|\__, |_|_|_| |_|\__, |___/
           |___/           |___/


  install                      Copy build artifacts to prefix path
  uninstall                    Remove build artifacts from prefix path
  info                         
         _       _ _
     ___(_) __ _| (_)_ __   __ _ ___
    |_  | |/ _' | | | '_ \ / _' / __|
     / /| | (_| | | | | | | (_| \__ \
    /___|_|\__, |_|_|_| |_|\__, |___/
           |___/           |___/


  ziglings (default)           Check all ziglings
  1_test                       Run 001_hello.zig without checking output
  1_install                    Install 001_hello.zig to zig-cache/bin
  1                            Check 001_hello.zig only
  1_start                      Check all solutions starting at 001_hello.zig
  2_test                       Run 002_std.zig without checking output
  2_install                    Install 002_std.zig to zig-cache/bin
  2                            Check 002_std.zig only
  2_start                      Check all solutions starting at 002_std.zig
  3_test                       Run 003_assignment.zig without checking output
  3_install                    Install 003_assignment.zig to zig-cache/bin
  3                            Check 003_assignment.zig only
  3_start                      Check all solutions starting at 003_assignment.zig
  4_test                       Run 004_arrays.zig without checking output
  4_install                    Install 004_arrays.zig to zig-cache/bin
  4                            Check 004_arrays.zig only
  4_start                      Check all solutions starting at 004_arrays.zig
  5_test                       Run 005_arrays2.zig without checking output
  5_install                    Install 005_arrays2.zig to zig-cache/bin
  5                            Check 005_arrays2.zig only
  5_start                      Check all solutions starting at 005_arrays2.zig
  6_test                       Run 006_strings.zig without checking output
  6_install                    Install 006_strings.zig to zig-cache/bin
  6                            Check 006_strings.zig only
  6_start                      Check all solutions starting at 006_strings.zig
  7_test                       Run 007_strings2.zig without checking output
  7_install                    Install 007_strings2.zig to zig-cache/bin
  7                            Check 007_strings2.zig only
  7_start                      Check all solutions starting at 007_strings2.zig
  8_test                       Run 008_quiz.zig without checking output
  8_install                    Install 008_quiz.zig to zig-cache/bin
  8                            Check 008_quiz.zig only
  8_start                      Check all solutions starting at 008_quiz.zig
  9_test                       Run 009_if.zig without checking output
  9_install                    Install 009_if.zig to zig-cache/bin
  9                            Check 009_if.zig only
  9_start                      Check all solutions starting at 009_if.zig
  10_test                      Run 010_if2.zig without checking output
  10_install                   Install 010_if2.zig to zig-cache/bin
  10                           Check 010_if2.zig only
  10_start                     Check all solutions starting at 010_if2.zig
  11_test                      Run 011_while.zig without checking output
  11_install                   Install 011_while.zig to zig-cache/bin
  11                           Check 011_while.zig only
  11_start                     Check all solutions starting at 011_while.zig
  12_test                      Run 012_while2.zig without checking output
  12_install                   Install 012_while2.zig to zig-cache/bin
  12                           Check 012_while2.zig only
  12_start                     Check all solutions starting at 012_while2.zig
  13_test                      Run 013_while3.zig without checking output
  13_install                   Install 013_while3.zig to zig-cache/bin
  13                           Check 013_while3.zig only
  13_start                     Check all solutions starting at 013_while3.zig
  14_test                      Run 014_while4.zig without checking output
  14_install                   Install 014_while4.zig to zig-cache/bin
  14                           Check 014_while4.zig only
  14_start                     Check all solutions starting at 014_while4.zig
  15_test                      Run 015_for.zig without checking output
  15_install                   Install 015_for.zig to zig-cache/bin
  15                           Check 015_for.zig only
  15_start                     Check all solutions starting at 015_for.zig
  16_test                      Run 016_for2.zig without checking output
  16_install                   Install 016_for2.zig to zig-cache/bin
  16                           Check 016_for2.zig only
  16_start                     Check all solutions starting at 016_for2.zig
  17_test                      Run 017_quiz2.zig without checking output
  17_install                   Install 017_quiz2.zig to zig-cache/bin
  17                           Check 017_quiz2.zig only
  17_start                     Check all solutions starting at 017_quiz2.zig
  18_test                      Run 018_functions.zig without checking output
  18_install                   Install 018_functions.zig to zig-cache/bin
  18                           Check 018_functions.zig only
  18_start                     Check all solutions starting at 018_functions.zig
  19_test                      Run 019_functions2.zig without checking output
  19_install                   Install 019_functions2.zig to zig-cache/bin
  19                           Check 019_functions2.zig only
  19_start                     Check all solutions starting at 019_functions2.zig
  20_test                      Run 020_quiz3.zig without checking output
  20_install                   Install 020_quiz3.zig to zig-cache/bin
  20                           Check 020_quiz3.zig only
  20_start                     Check all solutions starting at 020_quiz3.zig
  21_test                      Run 021_errors.zig without checking output
  21_install                   Install 021_errors.zig to zig-cache/bin
  21                           Check 021_errors.zig only
  21_start                     Check all solutions starting at 021_errors.zig
  22_test                      Run 022_errors2.zig without checking output
  22_install                   Install 022_errors2.zig to zig-cache/bin
  22                           Check 022_errors2.zig only
  22_start                     Check all solutions starting at 022_errors2.zig
  23_test                      Run 023_errors3.zig without checking output
  23_install                   Install 023_errors3.zig to zig-cache/bin
  23                           Check 023_errors3.zig only
  23_start                     Check all solutions starting at 023_errors3.zig
  24_test                      Run 024_errors4.zig without checking output
  24_install                   Install 024_errors4.zig to zig-cache/bin
  24                           Check 024_errors4.zig only
  24_start                     Check all solutions starting at 024_errors4.zig
  25_test                      Run 025_errors5.zig without checking output
  25_install                   Install 025_errors5.zig to zig-cache/bin
  25                           Check 025_errors5.zig only
  25_start                     Check all solutions starting at 025_errors5.zig
  26_test                      Run 026_hello2.zig without checking output
  26_install                   Install 026_hello2.zig to zig-cache/bin
  26                           Check 026_hello2.zig only
  26_start                     Check all solutions starting at 026_hello2.zig
  27_test                      Run 027_defer.zig without checking output
  27_install                   Install 027_defer.zig to zig-cache/bin
  27                           Check 027_defer.zig only
  27_start                     Check all solutions starting at 027_defer.zig
  28_test                      Run 028_defer2.zig without checking output
  28_install                   Install 028_defer2.zig to zig-cache/bin
  28                           Check 028_defer2.zig only
  28_start                     Check all solutions starting at 028_defer2.zig
  29_test                      Run 029_errdefer.zig without checking output
  29_install                   Install 029_errdefer.zig to zig-cache/bin
  29                           Check 029_errdefer.zig only
  29_start                     Check all solutions starting at 029_errdefer.zig
  30_test                      Run 030_switch.zig without checking output
  30_install                   Install 030_switch.zig to zig-cache/bin
  30                           Check 030_switch.zig only
  30_start                     Check all solutions starting at 030_switch.zig
  31_test                      Run 031_switch2.zig without checking output
  31_install                   Install 031_switch2.zig to zig-cache/bin
  31                           Check 031_switch2.zig only
  31_start                     Check all solutions starting at 031_switch2.zig
  32_test                      Run 032_unreachable.zig without checking output
  32_install                   Install 032_unreachable.zig to zig-cache/bin
  32                           Check 032_unreachable.zig only
  32_start                     Check all solutions starting at 032_unreachable.zig
  33_test                      Run 033_iferror.zig without checking output
  33_install                   Install 033_iferror.zig to zig-cache/bin
  33                           Check 033_iferror.zig only
  33_start                     Check all solutions starting at 033_iferror.zig
  34_test                      Run 034_quiz4.zig without checking output
  34_install                   Install 034_quiz4.zig to zig-cache/bin
  34                           Check 034_quiz4.zig only
  34_start                     Check all solutions starting at 034_quiz4.zig
  35_test                      Run 035_enums.zig without checking output
  35_install                   Install 035_enums.zig to zig-cache/bin
  35                           Check 035_enums.zig only
  35_start                     Check all solutions starting at 035_enums.zig
  36_test                      Run 036_enums2.zig without checking output
  36_install                   Install 036_enums2.zig to zig-cache/bin
  36                           Check 036_enums2.zig only
  36_start                     Check all solutions starting at 036_enums2.zig
  37_test                      Run 037_structs.zig without checking output
  37_install                   Install 037_structs.zig to zig-cache/bin
  37                           Check 037_structs.zig only
  37_start                     Check all solutions starting at 037_structs.zig
  38_test                      Run 038_structs2.zig without checking output
  38_install                   Install 038_structs2.zig to zig-cache/bin
  38                           Check 038_structs2.zig only
  38_start                     Check all solutions starting at 038_structs2.zig
  39_test                      Run 039_pointers.zig without checking output
  39_install                   Install 039_pointers.zig to zig-cache/bin
  39                           Check 039_pointers.zig only
  39_start                     Check all solutions starting at 039_pointers.zig
  40_test                      Run 040_pointers2.zig without checking output
  40_install                   Install 040_pointers2.zig to zig-cache/bin
  40                           Check 040_pointers2.zig only
  40_start                     Check all solutions starting at 040_pointers2.zig
  41_test                      Run 041_pointers3.zig without checking output
  41_install                   Install 041_pointers3.zig to zig-cache/bin
  41                           Check 041_pointers3.zig only
  41_start                     Check all solutions starting at 041_pointers3.zig
  42_test                      Run 042_pointers4.zig without checking output
  42_install                   Install 042_pointers4.zig to zig-cache/bin
  42                           Check 042_pointers4.zig only
  42_start                     Check all solutions starting at 042_pointers4.zig
  43_test                      Run 043_pointers5.zig without checking output
  43_install                   Install 043_pointers5.zig to zig-cache/bin
  43                           Check 043_pointers5.zig only
  43_start                     Check all solutions starting at 043_pointers5.zig
  44_test                      Run 044_quiz5.zig without checking output
  44_install                   Install 044_quiz5.zig to zig-cache/bin
  44                           Check 044_quiz5.zig only
  44_start                     Check all solutions starting at 044_quiz5.zig
  45_test                      Run 045_optionals.zig without checking output
  45_install                   Install 045_optionals.zig to zig-cache/bin
  45                           Check 045_optionals.zig only
  45_start                     Check all solutions starting at 045_optionals.zig
  46_test                      Run 046_optionals2.zig without checking output
  46_install                   Install 046_optionals2.zig to zig-cache/bin
  46                           Check 046_optionals2.zig only
  46_start                     Check all solutions starting at 046_optionals2.zig
  47_test                      Run 047_methods.zig without checking output
  47_install                   Install 047_methods.zig to zig-cache/bin
  47                           Check 047_methods.zig only
  47_start                     Check all solutions starting at 047_methods.zig
  48_test                      Run 048_methods2.zig without checking output
  48_install                   Install 048_methods2.zig to zig-cache/bin
  48                           Check 048_methods2.zig only
  48_start                     Check all solutions starting at 048_methods2.zig
  49_test                      Run 049_quiz6.zig without checking output
  49_install                   Install 049_quiz6.zig to zig-cache/bin
  49                           Check 049_quiz6.zig only
  49_start                     Check all solutions starting at 049_quiz6.zig
  50_test                      Run 050_no_value.zig without checking output
  50_install                   Install 050_no_value.zig to zig-cache/bin
  50                           Check 050_no_value.zig only
  50_start                     Check all solutions starting at 050_no_value.zig
  51_test                      Run 051_values.zig without checking output
  51_install                   Install 051_values.zig to zig-cache/bin
  51                           Check 051_values.zig only
  51_start                     Check all solutions starting at 051_values.zig
  52_test                      Run 052_slices.zig without checking output
  52_install                   Install 052_slices.zig to zig-cache/bin
  52                           Check 052_slices.zig only
  52_start                     Check all solutions starting at 052_slices.zig
  53_test                      Run 053_slices2.zig without checking output
  53_install                   Install 053_slices2.zig to zig-cache/bin
  53                           Check 053_slices2.zig only
  53_start                     Check all solutions starting at 053_slices2.zig
  54_test                      Run 054_manypointers.zig without checking output
  54_install                   Install 054_manypointers.zig to zig-cache/bin
  54                           Check 054_manypointers.zig only
  54_start                     Check all solutions starting at 054_manypointers.zig
  55_test                      Run 055_unions.zig without checking output
  55_install                   Install 055_unions.zig to zig-cache/bin
  55                           Check 055_unions.zig only
  55_start                     Check all solutions starting at 055_unions.zig
  56_test                      Run 056_unions2.zig without checking output
  56_install                   Install 056_unions2.zig to zig-cache/bin
  56                           Check 056_unions2.zig only
  56_start                     Check all solutions starting at 056_unions2.zig
  57_test                      Run 057_unions3.zig without checking output
  57_install                   Install 057_unions3.zig to zig-cache/bin
  57                           Check 057_unions3.zig only
  57_start                     Check all solutions starting at 057_unions3.zig
  58_test                      Run 058_quiz7.zig without checking output
  58_install                   Install 058_quiz7.zig to zig-cache/bin
  58                           Check 058_quiz7.zig only
  58_start                     Check all solutions starting at 058_quiz7.zig
  59_test                      Run 059_integers.zig without checking output
  59_install                   Install 059_integers.zig to zig-cache/bin
  59                           Check 059_integers.zig only
  59_start                     Check all solutions starting at 059_integers.zig
  60_test                      Run 060_floats.zig without checking output
  60_install                   Install 060_floats.zig to zig-cache/bin
  60                           Check 060_floats.zig only
  60_start                     Check all solutions starting at 060_floats.zig
  61_test                      Run 061_coercions.zig without checking output
  61_install                   Install 061_coercions.zig to zig-cache/bin
  61                           Check 061_coercions.zig only
  61_start                     Check all solutions starting at 061_coercions.zig
  62_test                      Run 062_loop_expressions.zig without checking output
  62_install                   Install 062_loop_expressions.zig to zig-cache/bin
  62                           Check 062_loop_expressions.zig only
  62_start                     Check all solutions starting at 062_loop_expressions.zig
  63_test                      Run 063_labels.zig without checking output
  63_install                   Install 063_labels.zig to zig-cache/bin
  63                           Check 063_labels.zig only
  63_start                     Check all solutions starting at 063_labels.zig
  64_test                      Run 064_builtins.zig without checking output
  64_install                   Install 064_builtins.zig to zig-cache/bin
  64                           Check 064_builtins.zig only
  64_start                     Check all solutions starting at 064_builtins.zig
  65_test                      Run 065_builtins2.zig without checking output
  65_install                   Install 065_builtins2.zig to zig-cache/bin
  65                           Check 065_builtins2.zig only
  65_start                     Check all solutions starting at 065_builtins2.zig
  66_test                      Run 066_comptime.zig without checking output
  66_install                   Install 066_comptime.zig to zig-cache/bin
  66                           Check 066_comptime.zig only
  66_start                     Check all solutions starting at 066_comptime.zig
  67_test                      Run 067_comptime2.zig without checking output
  67_install                   Install 067_comptime2.zig to zig-cache/bin
  67                           Check 067_comptime2.zig only
  67_start                     Check all solutions starting at 067_comptime2.zig
  68_test                      Run 068_comptime3.zig without checking output
  68_install                   Install 068_comptime3.zig to zig-cache/bin
  68                           Check 068_comptime3.zig only
  68_start                     Check all solutions starting at 068_comptime3.zig
  69_test                      Run 069_comptime4.zig without checking output
  69_install                   Install 069_comptime4.zig to zig-cache/bin
  69                           Check 069_comptime4.zig only
  69_start                     Check all solutions starting at 069_comptime4.zig
  70_test                      Run 070_comptime5.zig without checking output
  70_install                   Install 070_comptime5.zig to zig-cache/bin
  70                           Check 070_comptime5.zig only
  70_start                     Check all solutions starting at 070_comptime5.zig
  71_test                      Run 071_comptime6.zig without checking output
  71_install                   Install 071_comptime6.zig to zig-cache/bin
  71                           Check 071_comptime6.zig only
  71_start                     Check all solutions starting at 071_comptime6.zig
  72_test                      Run 072_comptime7.zig without checking output
  72_install                   Install 072_comptime7.zig to zig-cache/bin
  72                           Check 072_comptime7.zig only
  72_start                     Check all solutions starting at 072_comptime7.zig
  73_test                      Run 073_comptime8.zig without checking output
  73_install                   Install 073_comptime8.zig to zig-cache/bin
  73                           Check 073_comptime8.zig only
  73_start                     Check all solutions starting at 073_comptime8.zig
  74_test                      Run 074_comptime9.zig without checking output
  74_install                   Install 074_comptime9.zig to zig-cache/bin
  74                           Check 074_comptime9.zig only
  74_start                     Check all solutions starting at 074_comptime9.zig
  75_test                      Run 075_quiz8.zig without checking output
  75_install                   Install 075_quiz8.zig to zig-cache/bin
  75                           Check 075_quiz8.zig only
  75_start                     Check all solutions starting at 075_quiz8.zig
  76_test                      Run 076_sentinels.zig without checking output
  76_install                   Install 076_sentinels.zig to zig-cache/bin
  76                           Check 076_sentinels.zig only
  76_start                     Check all solutions starting at 076_sentinels.zig
  77_test                      Run 077_sentinels2.zig without checking output
  77_install                   Install 077_sentinels2.zig to zig-cache/bin
  77                           Check 077_sentinels2.zig only
  77_start                     Check all solutions starting at 077_sentinels2.zig
  78_test                      Run 078_sentinels3.zig without checking output
  78_install                   Install 078_sentinels3.zig to zig-cache/bin
  78                           Check 078_sentinels3.zig only
  78_start                     Check all solutions starting at 078_sentinels3.zig
  79_test                      Run 079_quoted_identifiers.zig without checking output
  79_install                   Install 079_quoted_identifiers.zig to zig-cache/bin
  79                           Check 079_quoted_identifiers.zig only
  79_start                     Check all solutions starting at 079_quoted_identifiers.zig
  80_test                      Run 080_anonymous_structs.zig without checking output
  80_install                   Install 080_anonymous_structs.zig to zig-cache/bin
  80                           Check 080_anonymous_structs.zig only
  80_start                     Check all solutions starting at 080_anonymous_structs.zig
  81_test                      Run 081_anonymous_structs2.zig without checking output
  81_install                   Install 081_anonymous_structs2.zig to zig-cache/bin
  81                           Check 081_anonymous_structs2.zig only
  81_start                     Check all solutions starting at 081_anonymous_structs2.zig
  82_test                      Run 082_anonymous_structs3.zig without checking output
  82_install                   Install 082_anonymous_structs3.zig to zig-cache/bin
  82                           Check 082_anonymous_structs3.zig only
  82_start                     Check all solutions starting at 082_anonymous_structs3.zig
  83_test                      Run 083_anonymous_lists.zig without checking output
  83_install                   Install 083_anonymous_lists.zig to zig-cache/bin
  83                           Check 083_anonymous_lists.zig only
  83_start                     Check all solutions starting at 083_anonymous_lists.zig
  92_test                      Run 092_interfaces.zig without checking output
  92_install                   Install 092_interfaces.zig to zig-cache/bin
  92                           Check 092_interfaces.zig only
  92_start                     Check all solutions starting at 092_interfaces.zig
  93_test                      Run 093_hello_c.zig without checking output
  93_install                   Install 093_hello_c.zig to zig-cache/bin
  93                           Check 093_hello_c.zig only
  93_start                     Check all solutions starting at 093_hello_c.zig
  94_test                      Run 094_c_math.zig without checking output
  94_install                   Install 094_c_math.zig to zig-cache/bin
  94                           Check 094_c_math.zig only
  94_start                     Check all solutions starting at 094_c_math.zig
  95_test                      Run 095_for_loops.zig without checking output
  95_install                   Install 095_for_loops.zig to zig-cache/bin
  95                           Check 095_for_loops.zig only
  95_start                     Check all solutions starting at 095_for_loops.zig
  96_test                      Run 096_memory_allocation.zig without checking output
  96_install                   Install 096_memory_allocation.zig to zig-cache/bin
  96                           Check 096_memory_allocation.zig only
  96_start                     Check all solutions starting at 096_memory_allocation.zig
  999_test                     Run 999_the_end.zig without checking output
  999_install                  Install 999_the_end.zig to zig-cache/bin
  999                          Check 999_the_end.zig only
  999_start                    Check all solutions starting at 999_the_end.zig

I will fix it.