Remove -fopenmp, fix pixman

Possibly this is not wise, but with -fopenmp -lgomp is automatically added by the toolchain, and I didn't have -lgomp.

Ideally we'd detect when this will work and then leave it in there.

/cc @sharpie @mikemcquaid @jacknagel

Library/ENV/4.3/cc

@@ -100,6 +100,9 @@ class Cmd
            %r{^-[IL]/opt/local}, %r{^-[IL]/sw},    # no macports/fink
            %r{^-[IL]/usr/X11}, %r{^-[IL]/opt/X11}, # we add X11 ourselves
            '-pedantic', '-pedantic-errors'
+      when /^-fopenmp/
+        # remove this arg: it fails the build with:
+        #   ld: library not found for -lgomp
       when /^-W.*/
         args << arg if arg =~ /^-Wl,/
       when '-macosx_version_min', '-dylib_install_name'