added glActiveStencilFaceEXT
diff --git a/progs/util/extfuncs.h b/progs/util/extfuncs.h
index f5ea5fe..13067cd 100644
--- a/progs/util/extfuncs.h
+++ b/progs/util/extfuncs.h
@@ -56,6 +56,8 @@
 static PFNGLGENVERTEXARRAYSAPPLEPROC glGenVertexArraysAPPLE_func = NULL;
 static PFNGLISVERTEXARRAYAPPLEPROC glIsVertexArrayAPPLE_func = NULL;
 
+/* GL_EXT_stencil_two_side */
+static PFNGLACTIVESTENCILFACEEXTPROC glActiveStencilFaceEXT_func = NULL;
 
 
 static void
@@ -114,5 +116,7 @@
    glGenVertexArraysAPPLE_func = (PFNGLGENVERTEXARRAYSAPPLEPROC) glutGetProcAddress("glGenVertexArraysAPPLE");
    glIsVertexArrayAPPLE_func = (PFNGLISVERTEXARRAYAPPLEPROC) glutGetProcAddress("glIsVertexArrayAPPLE");
 
+   /* GL_EXT_stencil_two_side */
+   glActiveStencilFaceEXT_func = (PFNGLACTIVESTENCILFACEEXTPROC) glutGetProcAddress("glActiveStencilFaceEXT");
 }