cogl: Stop auto generating gl/egl headers

They contain nothing that requires generating those headers
automatically
so simplify the whole thing

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3405>

cogl/cogl/cogl-egl-defines.h

@@ -32,6 +32,8 @@
 
 #ifdef HAVE_EGL
 
-@COGL_EGL_INCLUDES@
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <EGL/eglmesaext.h>
 
 #endif /* HAVE_EGL */

cogl/cogl/cogl-gl-header.h

@@ -36,7 +36,12 @@
 
 #include "config.h"
 
-@COGL_GL_HEADER_INCLUDES@
+#if defined(HAVE_GL)
+#include <GL/gl.h>
+#elif defined(HAVE_GLES2)
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#endif
 
 #ifndef GL_OES_EGL_image
 #define GLeglImageOES void *

cogl/cogl/meson.build

@@ -1,44 +1,6 @@
 cogl_cogl_includesubdir = cogl_includesubdir / 'cogl'
 cogl_cogl_includedir = cogl_includedir / 'cogl'
 
-if have_gl
-  cogl_gl_header_includes = ['GL/gl.h']
-elif have_gles2
-  cogl_gl_header_includes = ['GLES2/gl2.h', 'GLES2/gl2ext.h']
-else
-  error('Neither GLES2 or OpenGL was enabled')
-endif
-
-cogl_gl_header_includes_string = ''
-foreach gl_header : cogl_gl_header_includes
- cogl_gl_header_includes_string += '#include <@0@>\n'.format(gl_header)
-endforeach
-
-cdata = configuration_data()
-cdata.set('COGL_GL_HEADER_INCLUDES', cogl_gl_header_includes_string)
-
-cogl_gl_header_h = configure_file(
-  input: 'cogl-gl-header.h.in',
-  output: 'cogl-gl-header.h',
-  configuration: cdata,
-  install: false,
-)
-
-if have_egl
-  cogl_egl_includes_string = '#include <EGL/egl.h>\n#include <EGL/eglext.h>\n#include <EGL/eglmesaext.h>'
-else
-  cogl_egl_includes_string = ''
-endif
-
-cdata = configuration_data()
-cdata.set('COGL_EGL_INCLUDES', cogl_egl_includes_string)
-cogl_egl_defines_h = configure_file(
-  input: 'cogl-egl-defines.h.in',
-  output: 'cogl-egl-defines.h',
-  configuration: cdata,
-  install: false,
-)
-
 cogl_deprecated_headers = [
   'deprecated/cogl-program.h',
   'deprecated/cogl-shader.h',
@@ -172,6 +134,12 @@ if have_gles2
   cogl_driver_sources += gles_driver_sources
 endif
 
+if have_gl or have_gles2
+  cogl_nonintrospected_headers += [
+    'cogl-gl-header.h'
+  ]
+endif
+
 cogl_sources = [
   cogl_driver_sources,
   'winsys/cogl-winsys-private.h',
@@ -362,7 +330,7 @@ endif
 if have_egl
   cogl_nonintrospected_headers += [
     'cogl-egl.h',
-    cogl_egl_defines_h,
+    'cogl-egl-defines.h',
   ]
   cogl_sources += [
     'cogl-egl-private.h',

meson.build

@@ -214,6 +214,10 @@ if have_gles2
   endif
 endif
 
+if not have_gl and not have_gles2
+  error('Neither GLES2 or OpenGL was enabled')
+endif
+
 if have_wayland
   wayland_server_dep = dependency('wayland-server', version: wayland_server_req)
   wayland_client_dep = dependency('wayland-client', version: wayland_server_req)