vl: Enable DRM by default.

If libdrm is found the pipe loader enables drm anyway, and that is
pretty much the only extra dependency this code has.

This enables creating libva display using a drm fd without having
to enable the DRM (GBM really) backend of EGL, which is completely
unrelated.

Leaving the X11 platforms alone as they would still result in the
additional inclusion of extra deps.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

meson.build

@@ -589,9 +589,9 @@ if not system_has_kms_drm
   else
     _va = 'false'
   endif
-elif not (with_platform_x11 or with_platform_drm)
+elif not (with_platform_x11 or dep_libdrm.found())
   if _va == 'true'
-    error('VA state tracker requires X11 or drm or wayland platform support.')
+    error('VA state tracker requires X11 platform support or libdrm.')
   else
     _va = 'false'
   endif

src/gallium/auxiliary/meson.build

@@ -490,7 +490,7 @@ if with_dri2 and with_platform_x11
     files_libgalliumvlwinsys += files('vl/vl_winsys_dri3.c')
   endif
 endif
-if with_platform_drm
+if dep_libdrm.found()
   files_libgalliumvlwinsys += files('vl/vl_winsys_drm.c')
 endif
 

src/gallium/auxiliary/vl/vl_winsys.h

@@ -92,7 +92,7 @@ static inline struct vl_screen *
 vl_dri3_screen_create(void *display, int screen) { return NULL; };
 #endif
 
-#ifdef HAVE_DRM_PLATFORM
+#ifdef HAVE_LIBDRM
 struct vl_screen *
 vl_drm_screen_create(int fd);
 #else