XQuartz: remove undefined XSERVER_CFLAGS variable

This is a variable local to configure.ac which is not AC_SUBST()
It is undefined in any generated Makefile.

Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
Signed-off-by: Gaetan Nadon <memsize@videotron.ca>
Signed-off-by: Keith Packard <keithp@keithp.com>

hw/xquartz/GL/Makefile.am

@@ -1,5 +1,5 @@
 noinst_LTLIBRARIES = libCGLCore.la
-AM_CFLAGS = $(XSERVER_CFLAGS) $(DIX_CFLAGS)
+AM_CFLAGS = $(DIX_CFLAGS)
 AM_CPPFLAGS = \
 	-I$(top_srcdir) \
 	-I$(top_srcdir)/glx \

hw/xquartz/Makefile.am

@@ -1,6 +1,6 @@
 noinst_LTLIBRARIES = libXquartz.la
-AM_CFLAGS = $(XSERVER_CFLAGS) $(DIX_CFLAGS)
-AM_OBJCFLAGS = $(XSERVER_CFLAGS) $(DIX_CFLAGS)
+AM_CFLAGS = $(DIX_CFLAGS)
+AM_OBJCFLAGS = $(DIX_CFLAGS)
 AM_CPPFLAGS = \
 	-DBUILD_DATE=\"$(BUILD_DATE)\" \
 	-DXSERVER_VERSION=\"$(VERSION)\" \

hw/xquartz/mach-startup/Makefile.am

@@ -3,7 +3,7 @@ AM_CPPFLAGS = \
 	-DXSERVER_VERSION=\"$(VERSION)\" \
 	-DX11BINDIR=\"$(bindir)\"
 
-AM_CFLAGS = $(XSERVER_CFLAGS) $(DIX_CFLAGS)
+AM_CFLAGS = $(DIX_CFLAGS)
 
 x11appdir = $(APPLE_APPLICATIONS_DIR)/$(APPLE_APPLICATION_NAME).app/Contents/MacOS
 x11app_PROGRAMS = X11.bin

hw/xquartz/xpr/Makefile.am

@@ -1,6 +1,6 @@
 noinst_LTLIBRARIES = libXquartzXpr.la
 
-AM_CFLAGS =  $(XSERVER_CFLAGS) $(DIX_CFLAGS)
+AM_CFLAGS =  $(DIX_CFLAGS)
 AM_CPPFLAGS = \
 	-I$(srcdir) -I$(srcdir)/.. \
 	-I$(top_srcdir)/miext \