Log Message:
Fix last commit:
1.) The check in "pkgsrc/x11/pixman/Makefile" was incorrect and always
    disabled SSE2. Remove it which also fixes the Mac OS X build as
    the necessary patch for the test program gets applied again.
2.) Correct the existing SSE2 handling in "pkgsrc/x11/pixman/hacks.mk":
    - Correctly match the various GCC versions.
    - Disable SSE2 for both amd64 and i386 when old versions of GCC
      are used.