build, compositor-drm: fix output name constants another way

Bumping libdrm requirement by 3 years just for output connector name
constants was a bit much. Fix the problem introduced in
89c49b3060 by conditionally using the new
additions.

Both VIRTUAL and DSI came in the same libdrm commit
566c3ce877a4be72697e15cdfc421ce965f7c37d, so we check only for DSI.

This patch also reverts faee330c5e.

Reported-by: Eugen Friedrich <friedrix@gmail.com>
Cc: Derek Foreman <derekf@osg.samsung.com>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Acked-by: Bryce Harrington <bryce@osg.samsung.com>

configure.ac

@@ -171,7 +171,7 @@ AC_ARG_ENABLE(drm-compositor, [  --enable-drm-compositor],,
 AM_CONDITIONAL(ENABLE_DRM_COMPOSITOR, test x$enable_drm_compositor = xyes)
 if test x$enable_drm_compositor = xyes; then
   AC_DEFINE([BUILD_DRM_COMPOSITOR], [1], [Build the DRM compositor])
-  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.59 gbm mtdev >= 1.1.0])
+  PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm mtdev >= 1.1.0])
   PKG_CHECK_MODULES(DRM_COMPOSITOR_GBM, [gbm >= 10.2],
 		    [AC_DEFINE([HAVE_GBM_FD_IMPORT], 1, [gbm supports dmabuf import])],
 		    [AC_MSG_WARN([gbm does not support dmabuf import, will omit that capability])])

src/compositor-drm.c

@@ -1760,8 +1760,10 @@ static const char * const connector_type_names[] = {
 	[DRM_MODE_CONNECTOR_HDMIB]       = "HDMI-B",
 	[DRM_MODE_CONNECTOR_TV]          = "TV",
 	[DRM_MODE_CONNECTOR_eDP]         = "eDP",
+#ifdef DRM_MODE_CONNECTOR_DSI
 	[DRM_MODE_CONNECTOR_VIRTUAL]     = "Virtual",
 	[DRM_MODE_CONNECTOR_DSI]         = "DSI",
+#endif
 };
 
 static char *