Foundation: made compile on Xcode 6.1 with clang (which is only needed for development; it does not work on Mac OS X)

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
mySTEP.make: remove OTHER_CFLAGS because they interfere with Xcode builds (redefining -isysroot / to use no SDK)

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>