drm: remove no longer needed VISIBILITY_CFLAGS

With earlier commits we've annotated the private symbols, thus
we no longer require the -fvisibility=hidden CFLAGS.

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Michel Dänzer <michel.daenzer@amd.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

configure.ac

@@ -403,21 +403,6 @@ AC_ARG_WITH([kernel-source],
 	    [kernel_source="$with_kernel_source"])
 AC_SUBST(kernel_source)
 
-dnl Add flags for gcc and g++
-if test "x$GCC" = xyes; then
-    # Enable -fvisibility=hidden if using a gcc that supports it
-    save_CFLAGS="$CFLAGS"
-    AC_MSG_CHECKING([whether $CC supports -fvisibility=hidden])
-    VISIBILITY_CFLAGS="-fvisibility=hidden"
-    CFLAGS="$CFLAGS $VISIBILITY_CFLAGS"
-    AC_LINK_IFELSE([AC_LANG_PROGRAM()], AC_MSG_RESULT([yes]),
-                   [VISIBILITY_CFLAGS=""; AC_MSG_RESULT([no])]);
-
-    # Restore CFLAGS; VISIBILITY_CFLAGS are added to it where needed.
-    CFLAGS=$save_CFLAGS
-    AC_SUBST([VISIBILITY_CFLAGS])
-fi
-
 AC_MSG_CHECKING([whether $CC supports __attribute__((visibility))])
 AC_LINK_IFELSE([AC_LANG_PROGRAM([
     int foo_default( void ) __attribute__((visibility("default")));

exynos/Makefile.am

@@ -1,6 +1,5 @@
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	-I$(top_srcdir)/include/drm

freedreno/Makefile.am

@@ -3,7 +3,6 @@ include Makefile.sources
 
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	-I$(top_srcdir)/include/drm

intel/Makefile.am

@@ -26,7 +26,6 @@ include Makefile.sources
 
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	$(PCIACCESS_CFLAGS) \

nouveau/Makefile.am

@@ -2,7 +2,6 @@ include Makefile.sources
 
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	-I$(top_srcdir)/include/drm \

omap/Makefile.am

@@ -1,6 +1,5 @@
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	-I$(top_srcdir)/include/drm

radeon/Makefile.am

@@ -26,7 +26,6 @@ include Makefile.sources
 
 AM_CFLAGS = \
 	$(WARN_CFLAGS) \
-	$(VISIBILITY_CFLAGS) \
 	-I$(top_srcdir) \
 	$(PTHREADSTUBS_CFLAGS) \
 	-I$(top_srcdir)/include/drm

tegra/Makefile.am

@@ -4,7 +4,6 @@ AM_CPPFLAGS = \
 
 AM_CFLAGS = \
 	@PTHREADSTUBS_CFLAGS@ \
-	$(VISIBILITY_CFLAGS) \
 	$(WARN_CFLAGS)
 
 libdrm_tegra_ladir = $(libdir)