The -fdiagnostics-color flag is only available on GCC >= 4.9, for
older versions this could raise an error in certain circumstances
(such as when using ccache). Instead, since -fdiagnostic-color=auto
by default in gcc-4.9, simply set the required environment variable
to the default one if it's undefined.
Based mostly on the systemd commit
f44541bc by Michal Schmidt.
ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
AM_MAKEFLAGS = --no-print-directory
+GCC_COLORS ?= 'yes'
+export GCC_COLORS
+
AM_CPPFLAGS = \
-include $(top_builddir)/config.h \
-I$(top_srcdir)/libkmod \
-Wuninitialized \
-fno-common \
-fdiagnostics-show-option \
- -fdiagnostics-color=auto \
-fvisibility=hidden \
-ffunction-sections \
-fdata-sections])