patch to find Solaris libdrm include files 

not suitable for upstream

--- src/gbm/meson.build	2022-03-10 19:38:32.863605150 -0800
+++ src/gbm/meson.build	2022-03-10 19:39:33.969269587 -0800
@@ -48,7 +48,7 @@
 libgbm = shared_library(
   'gbm',
   files_gbm,
-  include_directories : incs_gbm,
+  include_directories : [incs_gbm, '/usr/include/libdrm'],
   c_args : [args_gbm],
   link_args : [ld_args_gc_sections],
   link_with : libloader,

--- src/mesa/drivers/x11/meson.build	2022-03-11 13:30:50.456660787 -0800
+++ src/mesa/drivers/x11/meson.build	2022-03-11 13:30:38.493435068 -0800
@@ -34,6 +34,6 @@
   ],
   link_with : [libmesa_classic, libglapi_static, gl_link_with],
   dependencies : [idep_mesautil, dep_x11, dep_xext, dep_xcb, dep_thread],
-  version : '1.6.0',
+  version : '1.2.0',
   install : true,
 )

Without forcing dri to true, we cannot build libEGL

Not suitable for upstream

--- meson.build	2022-03-15 20:23:43.570325697 -0700
+++ meson.build	2022-03-15 20:28:41.286497416 -0700
@@ -196,6 +196,7 @@
 with_dri_nouveau = dri_drivers.contains('nouveau')
 
 with_dri = dri_drivers.length() != 0
+with_dri = true
 
 gallium_drivers = get_option('gallium-drivers')
 if gallium_drivers.contains('auto')