Add support for Mesa's GLES1 implementation.

Mesa reports "OpenGL ES-CM 1.1", so we need to not look for a space
after "ES", and 1.1 is still a 1.0-compatible implementation.

src/gen_dispatch.py

@@ -347,7 +347,7 @@ class Generator(object):
                     loader = 'epoxy_get_proc_address({0})'
             elif api == 'gles1':
                 human_name = 'OpenGL ES 1.0'
-                condition = '!epoxy_is_desktop_gl() && epoxy_gl_version() == 10'
+                condition = '!epoxy_is_desktop_gl() && epoxy_gl_version() >= 10 && epoxy_gl_version() < 20'
                 loader = 'epoxy_gles1_dlsym({0})'
             elif api == 'glx':
                 human_name = 'GLX {0}'.format(version)