Fixed build errors when PJ_OS_HAS_CHECK_STACK or PJ_HAS_TCP is disabled

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@153 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjlib/build/Makefile b/pjlib/build/Makefile
index c278f75..54f71bc 100644
--- a/pjlib/build/Makefile
+++ b/pjlib/build/Makefile
@@ -8,7 +8,7 @@
 ###############################################################################
 # Gather all flags.
 #
-export _CFLAGS 	:= -O2 -g $(CC_CFLAGS) $(OS_CFLAGS) $(HOST_CFLAGS) $(M_CFLAGS) \
+export _CFLAGS 	:= $(CC_CFLAGS) $(OS_CFLAGS) $(HOST_CFLAGS) $(M_CFLAGS) \
 		   $(CFLAGS) $(CC_INC)../include
 export _CXXFLAGS:= $(_CFLAGS) $(CC_CXXFLAGS) $(OS_CXXFLAGS) $(M_CXXFLAGS) \
 		   $(HOST_CXXFLAGS) $(CXXFLAGS)