egl/meson: Specify which symbols to export

The goal is to reduce symbol pollution, especially when building
with Perfetto support, which previously led to an excessive number
of exported symbols.

 objdump -T build/src/egl/libEGL_mesa.so.0.0.0 | grep perfetto | wc -l
 - before: 6963
 - after: 0

The new egl.sym version script explicitly exports only relevant egl and
MesaGLInteropEGL symbols, while marking all others as local.

While this change effectively removes all Perfetto-related exported symbols,
some C++ standard library symbols remain as undefined. These are pulled in
by the linker due to dependencies.

Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33001>

src/egl/egl-glvnd.sym

@@ -0,0 +1,6 @@
+{
+	global:
+		__egl_Main;
+	local:
+		*;
+};

src/egl/egl.sym

@@ -0,0 +1,7 @@
+{
+	global:
+		egl*;
+		MesaGLInteropEGL*;
+	local:
+		*;
+};

src/egl/meson.build

@@ -5,6 +5,8 @@ inc_egl = include_directories('.', 'main')
 
 c_args_for_egl = [asan_c_args]
 cpp_args_for_egl = []
+link_args_for_egl = []
+link_deps_for_egl = []
 link_for_egl = [libpipe_loader_dynamic]
 if with_dri
   link_for_egl += libgallium_dri
@@ -172,6 +174,20 @@ else
   )
 endif
 
+if with_ld_version_script
+  if with_glvnd
+    link_args_for_egl += [
+      '-Wl,--version-script', join_paths(meson.current_source_dir(), 'egl-glvnd.sym')
+    ]
+    link_deps_for_egl += files('egl-glvnd.sym')
+  else
+    link_args_for_egl += [
+      '-Wl,--version-script', join_paths(meson.current_source_dir(), 'egl.sym')
+    ]
+    link_deps_for_egl += files('egl.sym')
+  endif
+endif
+
 egl_def = custom_target(
   'egl.def',
   input: 'main/egl.def.in',
@@ -190,7 +206,8 @@ libegl = shared_library(
   gnu_symbol_visibility : 'hidden',
   include_directories : incs_for_egl,
   link_with : [link_for_egl, libglapi],
-  link_args : [ld_args_bsymbolic, ld_args_gc_sections],
+  link_args : [ld_args_bsymbolic, ld_args_gc_sections, link_args_for_egl],
+  link_depends : [link_deps_for_egl],
   dependencies : [deps_for_egl, dep_dl, dep_libdrm, dep_clock, dep_thread, idep_mesautil],
   install : true,
   version : egl_lib_version,