lib: Only compile igt_vc4 is we have it

Unbreaks compilation fail.

Also appease gcc in gem_exec_basic because.

Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

lib/Makefile.am

@@ -8,6 +8,12 @@ include Makefile.sources
 noinst_LTLIBRARIES = libintel_tools.la
 noinst_HEADERS = check-ndebug.h
 
+if HAVE_VC4
+	libintel_tools_la_SOURCES += 	\
+		igt_vc4.c		\
+		igt_vc4.h
+endif
+
 AM_CPPFLAGS = -I$(top_srcdir)
 AM_CFLAGS = $(DRM_CFLAGS) $(CWARNFLAGS) $(LIBUNWIND_CFLAGS) $(DEBUG_CFLAGS) \
 	    -DIGT_SRCDIR=\""$(abs_top_srcdir)/tests"\" \

lib/Makefile.sources

@@ -16,8 +16,6 @@ libintel_tools_la_SOURCES = 	\
 	igt_gt.h		\
 	igt_stats.c		\
 	igt_stats.h		\
-	igt_vc4.c		\
-	igt_vc4.h		\
 	instdone.c		\
 	instdone.h		\
 	intel_batchbuffer.c	\