meson: Build i915

Build i915 with meson. More or less copied from i965, with all
the unneeded cruft removed, and the libdrm_intel dependency added.

Cc: Dylan Baker <dylan@pnwbakers.com>
Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

meson.build

@@ -72,16 +72,23 @@ if (with_gles1 or with_gles2) and not with_opengl
 endif
 
 with_dri = false
+with_dri_i915 = false
 with_dri_i965 = false
 with_dri_swrast = false
 _drivers = get_option('dri-drivers')
 if _drivers != ''
   _split = _drivers.split(',')
+  with_dri_i915 = _split.contains('i915')
   with_dri_i965 = _split.contains('i965')
   with_dri_swrast = _split.contains('swrast')
   with_dri = true
 endif
 
+dep_libdrm_intel = []
+if with_dri_i915
+  dep_libdrm_intel = dependency('libdrm_intel', version : '>= 2.4.75')
+endif
+
 if not with_dri
   with_gles1 = false
   with_gles2 = false