treewide: NIX_*_COMPILE -> string

pkgs/development/libraries/gtk/3.x.nix

@@ -88,10 +88,7 @@ stdenv.mkDerivation rec {
 
   # These are the defines that'd you'd get with --enable-debug=minimum (default).
   # See: https://developer.gnome.org/gtk3/stable/gtk-building.html#extra-configuration-options
-  NIX_CFLAGS_COMPILE = [
-    "-DG_ENABLE_DEBUG"
-    "-DG_DISABLE_CAST_CHECKS"
-  ];
+  NIX_CFLAGS_COMPILE = "-DG_ENABLE_DEBUG -DG_DISABLE_CAST_CHECKS";
 
   postPatch = ''
     files=(

pkgs/development/libraries/ilmbase/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
   depsBuildBuild = [ buildPackages.stdenv.cc ];
   nativeBuildInputs = [ automake autoconf libtool which ];
 
-  NIX_CFLAGS_LINK = [ "-pthread" ];
+  NIX_CFLAGS_LINK = "-pthread";
 
   patches = [
     ./bootstrap.patch

pkgs/development/libraries/libcaca/default.nix

@@ -19,12 +19,12 @@ stdenv.mkDerivation rec {
     (if x11Support then "--enable-x11" else "--disable-x11")
     ];
 
-  NIX_CFLAGS_COMPILE = stdenv.lib.optional (!x11Support) "-DX_DISPLAY_MISSING";
+  NIX_CFLAGS_COMPILE = stdenv.lib.optionalString (!x11Support) "-DX_DISPLAY_MISSING";
 
   enableParallelBuilding = true;
 
   propagatedBuildInputs = [ ncurses zlib pkgconfig (imlib2.override { inherit x11Support; }) ]
-    ++ stdenv.lib.optionals x11Support [ libX11 libXext];
+    ++ stdenv.lib.optionals x11Support [ libX11 libXext ];
 
   postInstall = ''
     mkdir -p $dev/bin

pkgs/development/libraries/smpeg/default.nix

@@ -40,7 +40,7 @@ stdenv.mkDerivation rec {
       --prefix PKG_CONFIG_PATH ":" "${SDL.dev}/lib/pkgconfig"
   '';
 
-  NIX_LDFLAGS = [ "-lX11" ];
+  NIX_LDFLAGS = "-lX11";
 
   meta = {
     homepage = http://icculus.org/smpeg/;