scons: Add support for GLES.

GLES can be enabled by running scons with

  $ scons gles=yes

When gles=yes is given, the build is changed in three ways.  First,
libmesa.a will be built with FEATURE_ES1 and FEATURE_ES2.  This makes
DRI drivers and libEGL support and advertise GLES support.  Second, GLES
libraries will be created.  They are libGLESv1_CM, libGLESv2, and
libglapi.  Last, libGL or opengl32 will link to libglapi.  This change
is required as _glapi_* will be declared as __declspec(dllimport) in
libmesa.a on windows.  libmesa.a expects those symbols to be defined in
another DLL.  Due to this change to GL, GLES support is marked
experimental.

Note that GLES requires libxml2-python to generate some of its sources.

1 files changed, 12 insertions, 4 deletions

diff --git a/src/gallium/targets/egl-static/SConscript b/src/gallium/targets/egl-static/SConscript
index 381ef4e862d..c978934a0c8 100644
--- a/src/gallium/targets/egl-static/SConscript
+++ b/src/gallium/targets/egl-static/SConscript
@@ -58,10 +58,18 @@ if env['platform'] == 'windows':
     env.Prepend(LIBS = [
         ws_gdi,
     ])
-else:
-    # OpenGL
-    env.Append(CPPDEFINES = ['FEATURE_GL=1'])
-    env.Prepend(LIBS = ['GL', 'talloc', glsl, mesa])
+
+# OpenGL ES and OpenGL
+if env['gles']:
+    env.Append(CPPDEFINES = [
+        'FEATURE_GL=1',
+        'FEATURE_ES1=1',
+        'FEATURE_ES2=1'
+    ])
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    # manually add LIBPREFIX on windows
+    glapi_name = 'glapi' if env['platform'] != 'windows' else 'libglapi'
+    env.Prepend(LIBS = [glapi_name, talloc, glsl, mesa])
 
 # OpenVG
 if True: