perl540Packages.SDL: fix build

pkgs/development/perl-modules/sdl-compat-bit-depth.patch

@@ -0,0 +1,16 @@
+diff --git a/t/core_surface.t b/t/core_surface.t
+index 897536b6..03efa859 100644
+--- a/t/core_surface.t
++++ b/t/core_surface.t
+@@ -51,7 +51,10 @@ is( $image->h, 32, 'image has height' );
+ 
+ my $pixel_format = $image->format;
+ isa_ok( $pixel_format, 'SDL::PixelFormat' );
+-is( $pixel_format->BitsPerPixel,  8,   ' BitsPerPixel' );
++# the bitmap has a bitdepth of 4
++# SDL_classic could not allocate less than full bytes per pixel
++# sdl12-compat returns the actual bit depth of the image here
++is( $pixel_format->BitsPerPixel,  4,   ' BitsPerPixel' );
+ is( $pixel_format->BytesPerPixel, 1,   ' BytesPerPixel' );
+ is( $pixel_format->Rloss,         8,   ' Rloss' );
+ is( $pixel_format->Gloss,         8,   ' Gloss' );

pkgs/top-level/perl-packages.nix

@@ -30215,6 +30215,9 @@ with self;
     patches = [
       # https://github.com/PerlGameDev/SDL/pull/304
       ../development/perl-modules/sdl-modern-perl.patch
+      # sdl-compat correctly reports the bit depth of the test image,
+      # while SDL_classic rounded to the next byte
+      ../development/perl-modules/sdl-compat-bit-depth.patch
       (fetchpatch {
         url = "https://aur.archlinux.org/cgit/aur.git/plain/surface-xs-declare-calc-offset-earlier.diff?h=perl-sdl&id=d4b6da86d33046cde0e84fa2cd6eaccff1667cab";
         hash = "sha256-dQ2O4dO18diSAilSZrZj6II+mBuKKI3cx9fR1SJqUvo=";