Merge pull request #7023 from spwhitt/fftw

fftw: Fix Darwin build

pkgs/development/libraries/fftw/default.nix

@@ -16,16 +16,20 @@ stdenv.mkDerivation rec {
 
   configureFlags =
     [ "--enable-shared" "--disable-static"
-      "--enable-threads" "--enable-openmp" # very small wrappers
+      "--enable-threads"
     ]
     ++ optional (precision != "double") "--enable-${precision}"
     # all x86_64 have sse2
-    ++ optional stdenv.isx86_64 "--enable-sse2";
+    ++ optional stdenv.isx86_64 "--enable-sse2"
+    ++ optional (stdenv.cc.cc.isGNU or false) "--enable-openmp";
 
   enableParallelBuilding = true;
 
-  meta = {
+  meta = with stdenv.lib; {
     description = "Fastest Fourier Transform in the West library";
     homepage = http://www.fftw.org/;
+    license = licenses.gpl2Plus;
+    maintainers = [ maintainers.spwhitt ];
+    platforms = platforms.unix;
   };
 }