rtapi_compat: added rtapi_app checks to make sure the corresponding app
 	for a particular flavor is available
added xenomai_kernel
fix gcc version detection.
semicolon typo.
rtapi_compat: switched to checking for rtapi lib instead of rtapi app
Merge pull request #197 from kinsamanka/rtapi_compat_fix

Rtapi compat fix
Merge pull request #199 from bryant/small-fixes

Small fixes
betterer gcc version check.
Merge pull request #200 from bryant/small-fixes-fix

betterer gcc version check.
add glib-2.0 configure flag.
glib configure flag: fix typos, add disable msg.
make xinerama/emcsh optional.

Conflicts:
	src/emc/usr_intf/Submakefile
(temporarily) disable gl check
move python-dev check outside of BUILD_PYTHON

TOFIX: disable boost-python when --disable-python.
hack: remove -fno-strict-overflow for clang.
conditionally install xinerama-dependent files
include rpath in everything to make custom $PREFIX work.
stash commit