glx: include: meson_options.txt: Allow disabling DRI glx backends

This allows building the X server with glx and without mesa.
This also makes the X server optionally no longer be a loader for dri drivers.

Fixes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1638
Fixes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1819

Signed-off-by: stefan11111 <stefan11111@shitposting.expert>

glx/glxext.c

@@ -272,7 +272,12 @@ glxClientCallback(CallbackListPtr *list, void *closure, void *data)
 
 /************************************************************************/
 
-static __GLXprovider *__glXProviderStack = &__glXDRISWRastProvider;
+static __GLXprovider *__glXProviderStack =
+#ifdef BUILD_GLX_DRI
+                                           &__glXDRISWRastProvider;
+#else
+                                           NULL;
+#endif
 
 void
 GlxPushProvider(__GLXprovider * provider)

glx/meson.build

@@ -13,8 +13,6 @@ srcs_glx = [
     'glxcmds.c',
     'glxcmdsswap.c',
     'glxext.c',
-    'glxdriswrast.c',
-    'glxdricommon.c',
     'glxscreens.c',
     'render2.c',
     'render2swap.c',
@@ -30,6 +28,16 @@ srcs_glx = [
     'xfont.c',
 ]
 
+srcs_glxdri2 = []
+if build_glx_dri
+    srcs_glx += 'glx_dri/glxdriswrast.c'
+    srcs_glx += 'glx_dri/glxdricommon.c'
+
+    if build_dri2 or build_dri3
+        srcs_glxdri2 = files('glx_dri/glxdri2.c')
+    endif
+endif
+
 libxserver_glx = []
 if build_glx
     libxserver_glx = static_library('xserver_glx',
@@ -50,11 +58,6 @@ if build_glx
     )
 endif
 
-srcs_glxdri2 = []
-if build_dri2 or build_dri3
-    srcs_glxdri2 = files('glxdri2.c')
-endif
-
 srcs_vnd = [
     'vndcmds.c',
     'vndext.c',

include/meson.build

@@ -6,8 +6,6 @@ patch = version_split[2].to_int()
 # convert to the old-style 1.x.y version scheme used up to 1.20.x for backwards compatibility
 release = 1 * 10000000 + major * 100000 + minor * 1000 + patch
 
-dri_dep = dependency('dri', required: build_glx)
-
 # For feature macros we're using either false (boolean) or '1', which correspond to the macro being
 # not defined at all and defined to 1. This is to match autotools behavior and thus preserve
 # backwards  compatibility with all the existing code that uses #ifdef to check if feature is
@@ -222,7 +220,10 @@ conf_data.set('DPMSExtension', build_dpms ? '1' : false)
 conf_data.set('DRI2', build_dri2 ? '1' : false)
 conf_data.set('DRI3', build_dri3 ? '1' : false)
 if build_glx
-    conf_data.set_quoted('DRI_DRIVER_PATH', dri_dep.get_variable(pkgconfig : 'dridriverdir'))
+    if build_glx_dri
+        conf_data.set_quoted('DRI_DRIVER_PATH', dri_dep.get_variable(pkgconfig : 'dridriverdir'))
+        conf_data.set('BUILD_GLX_DRI', 1)
+    endif
 endif
 conf_data.set('MITSHM', build_mitshm ? '1' : false)
 conf_data.set('CONFIG_MITSHM', build_mitshm ? '1' : false)

meson.build

@@ -475,6 +475,20 @@ if build_glx
     build_hashtable = true
 endif
 
+dri_dep = dependency('dri', required: false)
+
+glx_dri_opt = get_option('glx_dri')
+build_glx_dri = (glx_dri_opt != 'false')
+if not dri_dep.found()
+    if glx_dri_opt == 'auto'
+        build_glx_dri = false
+    endif
+
+    if glx_dri_opt == 'true'
+        error('DRI glx backends requested, but dri.pc was not found')
+    endif
+endif
+
 libdrm_dep = dependency('libdrm', version: libdrm_req, required: false)
 
 if get_option('dri1') == 'auto'

meson_options.txt

@@ -37,6 +37,9 @@ option('fontrootdir', type: 'string',
 option('serverconfigdir', type: 'string',
         description: 'Miscellaneous server configuration files path. Default: $libdir/xorg')
 
+option('glx_dri', type: 'combo', choices: ['true', 'false', 'auto'], value: 'auto',
+        description: 'Build the dri-based glx backends. Default: true')
+
 option('glx', type: 'boolean', value: true)
 option('xdmcp', type: 'boolean', value: true)
 option('xdm-auth-1', type: 'boolean', value: true)