tachyon: Add darwin support

pkgs/development/libraries/tachyon/darwin.patch

@@ -0,0 +1,31 @@
+diff --git a/unix/Make-arch b/unix/Make-arch
+index 08afb85..822c4fc 100644
+--- a/unix/Make-arch
++++ b/unix/Make-arch
+@@ -924,7 +924,7 @@ macosx-thr:
+ 	$(MAKE) all \
+ 	"ARCH = macosx-thr" \
+ 	"CC = cc" \
+-	"CFLAGS = -Os -ffast-math -DBsd -DTHR -F/System/Library/Frameworks $(MISCFLAGS)" \
++	"CFLAGS = -Os -ffast-math -DBsd -DTHR $(MISCFLAGS)" \
+ 	"AR = ar" \
+ 	"ARFLAGS = r" \
+ 	"STRIP = strip" \
+@@ -946,7 +946,7 @@ macosx-x86-thr:
+ 	$(MAKE) all \
+ 	"ARCH = macosx-x86-thr" \
+ 	"CC = cc" \
+-	"CFLAGS = -O2 -ffast-math -DBsd -DTHR -F/System/Library/Frameworks $(MISCFLAGS)" \
++	"CFLAGS = -O2 -ffast-math -DBsd -DTHR $(MISCFLAGS)" \
+ 	"AR = ar" \
+ 	"ARFLAGS = r" \
+ 	"STRIP = strip" \
+@@ -957,7 +957,7 @@ macosx-x86-thr-ogl:
+ 	$(MAKE) all \
+ 	"ARCH = macosx-x86-thr-ogl" \
+ 	"CC = cc" \
+-	"CFLAGS = -O2 -ffast-math -DBsd -DTHR -I/usr/X11R6/include -F/System/Library/Frameworks $(MISCFLAGS) -DUSEOPENGL" \
++	"CFLAGS = -O2 -ffast-math -DBsd -DTHR -I/usr/X11R6/include $(MISCFLAGS) -DUSEOPENGL" \
+ 	"AR = ar" \
+ 	"ARFLAGS = r" \
+ 	"STRIP = strip" \

pkgs/development/libraries/tachyon/default.nix

@@ -50,7 +50,9 @@ stdenv.mkDerivation rec {
     ./no-absolute-paths.patch
     # Include new targets (like arm)
     ./make-archs.patch
-  ];
+  ] ++
+  # Ensure looks for nix-provided Carbon, not system frameworks
+  stdenv.lib.optional stdenv.isDarwin ./darwin.patch;
 
   installPhase = ''
     cd ../compile/${arch}
@@ -66,8 +68,7 @@ stdenv.mkDerivation rec {
     description = ''A Parallel / Multiprocessor Ray Tracing System'';
     license = stdenv.lib.licenses.bsd3;
     maintainers = [stdenv.lib.maintainers.raskin];
-    # darwin fails due to missing Carbon.h, even though Carbon is a build input
-    platforms = with stdenv.lib.platforms; linux ++ cygwin;
+    platforms = with stdenv.lib.platforms; linux ++ cygwin ++ darwin;
     homepage = http://jedi.ks.uiuc.edu/~johns/tachyon/;
   };
 }