diff --git a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
index 758e064a05..d4a2ded63b 100644
--- a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
+++ b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
@@ -347,7 +347,7 @@ reset() {
 
   _glBlendEquation = NULL;
   if (has_extension("GL_EXT_blend_minmax") || is_at_least_version(1, 2)) {
-    _glBlendEquation = (PFNGLBLENDEQUATIONEXTPROC)
+    _glBlendEquation = (PFNGLBLENDEQUATIONPROC)
       get_extension_func(GLPREFIX_QUOTED, "BlendEquationEXT");
     if (_glBlendEquation == NULL) {
       GLCAT.warning()
@@ -360,7 +360,7 @@ reset() {
 
   _glBlendColor = NULL;
   if (has_extension("GL_EXT_blend_color") || is_at_least_version(1, 2)) {
-    _glBlendColor = (PFNGLBLENDCOLOREXTPROC)
+    _glBlendColor = (PFNGLBLENDCOLORPROC)
       get_extension_func(GLPREFIX_QUOTED, "BlendColorEXT");
     if (_glBlendColor == NULL) {
       GLCAT.warning()
@@ -3993,6 +3993,7 @@ get_fog_mode_type(Fog::Mode m) {
 GLenum CLP(GraphicsStateGuardian)::
 get_blend_equation_type(ColorBlendAttrib::Mode mode) {
   switch (mode) {
+  case ColorBlendAttrib::M_none:
   case ColorBlendAttrib::M_add:
     return GL_FUNC_ADD;
     
diff --git a/panda/src/glstuff/glGraphicsStateGuardian_src.h b/panda/src/glstuff/glGraphicsStateGuardian_src.h
index e0ea396bd3..98f51dbfe7 100644
--- a/panda/src/glstuff/glGraphicsStateGuardian_src.h
+++ b/panda/src/glstuff/glGraphicsStateGuardian_src.h
@@ -39,6 +39,16 @@
 class PlaneNode;
 class Light;
 
+// These typedefs are declared in glext.h, but we must repeat them
+// here, mainly because they will not be included from glext.h if the
+// system GL version matches or exceeds the GL version in which these
+// functions are defined, and the system gl.h sometimes doesn't
+// declare these typedefs.
+typedef void (APIENTRYP PFNGLACTIVETEXTUREPROC) (GLenum texture);
+typedef void (APIENTRYP PFNGLMULTITEXCOORD2FVPROC) (GLenum target, const GLfloat *v);
+typedef void (APIENTRYP PFNGLBLENDEQUATIONPROC) (GLenum mode);
+typedef void (APIENTRYP PFNGLBLENDCOLORPROC) (GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha);
+
 ////////////////////////////////////////////////////////////////////
 //       Class : GLGraphicsStateGuardian
 // Description : A GraphicsStateGuardian specialized for rendering
@@ -279,8 +289,8 @@ public:
   PFNGLACTIVETEXTUREPROC _glActiveTexture;
   PFNGLMULTITEXCOORD2FVPROC _glMultiTexCoord2fv;
 
-  PFNGLBLENDEQUATIONEXTPROC _glBlendEquation;
-  PFNGLBLENDCOLOREXTPROC _glBlendColor;
+  PFNGLBLENDEQUATIONPROC _glBlendEquation;
+  PFNGLBLENDCOLORPROC _glBlendColor;
 
   GLenum _edge_clamp;
   GLenum _border_clamp;
diff --git a/panda/src/glxdisplay/glxGraphicsStateGuardian.h b/panda/src/glxdisplay/glxGraphicsStateGuardian.h
index 1d640a1e4f..78fb11d208 100644
--- a/panda/src/glxdisplay/glxGraphicsStateGuardian.h
+++ b/panda/src/glxdisplay/glxGraphicsStateGuardian.h
@@ -30,6 +30,13 @@
 // includes gl.h).
 #include "glxext.h"
 
+// These typedefs are declared in glxext.h, but we must repeat them
+// here, mainly because they will not be included from glxext.h if the
+// system GLX version matches or exceeds the GLX version in which
+// these functions are defined, and the system glx.h sometimes doesn't
+// declare these typedefs.
+typedef __GLXextFuncPtr (* PFNGLXGETPROCADDRESSPROC) (const GLubyte *procName);
+
 ////////////////////////////////////////////////////////////////////
 //       Class : glxGraphicsStateGuardian
 // Description : A tiny specialization on GLGraphicsStateGuardian to