fix HAVE_CXX0X case on MinGW

During configure phase HAVE_CXX0X is determined and exposed
if the current gcc version supports it. With gcc 4.7.2 this
is the case. Activate it during compilation phase too.

Change-Id: I7b738de083fa337a422c20bdf88d9dca5f8303ed

solenv/gbuild/platform/WNT_INTEL_GCC.mk

@@ -85,8 +85,7 @@ gb_CFLAGS += --sysroot=$(SYSBASE)
 endif
 
 ifeq ($(HAVE_CXX0X),TRUE)
-# We can turn on additional useful checks with c++0x
-# FIXME still does not compile fully gb_CXXFLAGS += -std=gnu++0x
+gb_CXXFLAGS += -std=gnu++0x
 endif
 
 # At least sal defines its own __main, which would cause DLLs linking against