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.

5 files changed, 30 insertions, 4 deletions

diff --git a/src/gallium/state_trackers/wgl/SConscript b/src/gallium/state_trackers/wgl/SConscript
index 1b7597de44..7cb953ba74 100644
--- a/src/gallium/state_trackers/wgl/SConscript
+++ b/src/gallium/state_trackers/wgl/SConscript
@@ -15,6 +15,9 @@ env.AppendUnique(CPPDEFINES = [
     'BUILD_GL32', # declare gl* as __declspec(dllexport) in Mesa headers 
     'WIN32_LEAN_AND_MEAN', # http://msdn2.microsoft.com/en-us/library/6dwk3a1z.aspx
 ])
+if not env['gles']:
+    # prevent _glapi_* from being declared __declspec(dllimport)
+    env.Append(CPPDEFINES = ['_GLAPI_NO_EXPORTS'])
 
 sources = [
     'stw_context.c',
diff --git a/src/gallium/state_trackers/wgl/stw_device.c b/src/gallium/state_trackers/wgl/stw_device.c
index c4822d4d8a..4ece4e4979 100644
--- a/src/gallium/state_trackers/wgl/stw_device.c
+++ b/src/gallium/state_trackers/wgl/stw_device.c
@@ -170,7 +170,10 @@ stw_cleanup(void)
 
    _glthread_DESTROY_MUTEX(OneTimeLock);
 
+   /* glapi is statically linked: we can call the local destroy function. */
+#ifdef _GLAPI_NO_EXPORTS
    _glapi_destroy_multithread();
+#endif
 
 #ifdef DEBUG
    debug_memory_end(stw_dev->memdbg_no);
diff --git a/src/gallium/targets/egl-static/SConscript b/src/gallium/targets/egl-static/SConscript
index 381ef4e862..c978934a0c 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:
diff --git a/src/gallium/targets/libgl-gdi/SConscript b/src/gallium/targets/libgl-gdi/SConscript
index 6fa0851a1a..c088d4c2ae 100644
--- a/src/gallium/targets/libgl-gdi/SConscript
+++ b/src/gallium/targets/libgl-gdi/SConscript
@@ -37,6 +37,12 @@ drivers += [trace, rbug]
 
 env['no_import_lib'] = 1
 
+# when GLES is enabled, gl* and _glapi_* belong to bridge_glapi and
+# shared_glapi respectively
+if env['gles']:
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    glapi = [bridge_glapi, 'libglapi']
+
 opengl32 = env.SharedLibrary(
     target ='opengl32',
     source = sources,
diff --git a/src/gallium/targets/libgl-xlib/SConscript b/src/gallium/targets/libgl-xlib/SConscript
index d932736be7..9bb0a56525 100644
--- a/src/gallium/targets/libgl-xlib/SConscript
+++ b/src/gallium/targets/libgl-xlib/SConscript
@@ -16,6 +16,12 @@ env.Append(CPPDEFINES = ['USE_XSHM'])
 
 env.Prepend(LIBS = env['X11_LIBS'])
 
+# when GLES is enabled, gl* and _glapi_* belong to bridge_glapi and
+# shared_glapi respectively
+if env['gles']:
+    env.Prepend(LIBPATH = [shared_glapi.dir])
+    glapi = [bridge_glapi, 'glapi']
+
 env.Prepend(LIBS = [
     st_xlib,
     ws_xlib,