meson: Make the glvnd vendor name configurable

Leave the default as "mesa", but this enables parallel Mesa installs.

Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7674>

meson.build

@@ -478,6 +478,7 @@ if with_glx != 'disabled'
 endif
 
 with_glvnd = get_option('glvnd')
+glvnd_vendor_name = get_option('glvnd-vendor-name')
 if with_glvnd
   if with_platform_windows
     error('glvnd cannot be used on Windows')

meson_options.txt

@@ -289,6 +289,12 @@ option(
   value : 'auto',
   description : 'Build support for the Microsoft CLC to DXIL compiler'
 )
+option(
+  'glvnd-vendor-name',
+  type : 'string',
+  value : 'mesa',
+  description : 'Vendor name string to use for glvnd libraries'
+)
 option(
    'glx-read-only-text',
    type : 'boolean',

src/egl/main/50_mesa.json

@@ -1,6 +1,6 @@
 {
     "file_format_version" : "1.0.0",
     "ICD" : {
-        "library_path" : "libEGL_mesa.so.0"
+        "library_path" : "libEGL_@glvnd_vendor_name@.so.0"
     }
 }

src/egl/meson.build

@@ -144,13 +144,18 @@ if not with_glvnd
   egl_lib_name = 'EGL' + get_option('egl-lib-suffix')
   egl_lib_version = '1.0.0'
 else
-  egl_lib_name = 'EGL_mesa'
+  egl_lib_name = 'EGL_@0@'.format(glvnd_vendor_name)
   egl_lib_version = '0.0.0'
   deps_for_egl += dep_glvnd
   files_egl += [g_egldispatchstubs_h, g_egldispatchstubs_c]
   files_egl += files('main/eglglvnd.c', 'main/egldispatchstubs.c')
-  install_data(
-    'main/50_mesa.json',
+  glvnd_config = configuration_data()
+  glvnd_config.set('glvnd_vendor_name', get_option('glvnd-vendor-name'))
+  configure_file(
+    configuration: glvnd_config,
+    input : 'main/50_mesa.json',
+    output: '50_@0@.json'.format(glvnd_vendor_name),
+    install : true,
     install_dir : join_paths(get_option('datadir'), 'glvnd', 'egl_vendor.d')
   )
 endif

src/glx/meson.build

@@ -111,7 +111,7 @@ if not with_glvnd
   gl_lib_name = 'GL'
   gl_lib_version = '1.2.0'
 else
-  gl_lib_name = 'GLX_mesa'
+  gl_lib_name = 'GLX_@0@'.format(glvnd_vendor_name)
   gl_lib_version = '0.0.0'
   files_libglx += files(
     'g_glxglvnddispatchfuncs.c',