Use RUDIX_EXTRA_*FLAGS.
Use RUDIX_EXTRA_*FLAGS.

Use RUDIX_EXTRA_*FLAGS when defined. So you can use extra build
flags in your home directory like this:

cat ~/.rudix.conf
RUDIX_EXTRA_CFLAGS=-mmacosx-version-min=10.7
RUDIX_EXTRA_CXXFLAGS=-mmacosx-version-min=10.7
RUDIX_EXTRA_LDFLAGS=-mmacosx-version-min=10.7

Signed-off-by: Rudá Moura <3ceaf19413469ca7df9f6a96603874755ef36481@gmail.com>

rudix-mac/rudix,rudix-mac/rudix,FelixZhang00/rudix,FelixZhang00/rudix,FelixZhang00/rudix,FelixZhang00/rudix,rudix-mac/rudix