Fix compile error on OpenGL ES

panda/src/glstuff/glGraphicsStateGuardian_src.h

@@ -103,6 +103,7 @@ typedef void (APIENTRYP PFNGLMATRIXINDEXUIVARBPROC) (GLint size, const GLuint *i
 typedef void (APIENTRYP PFNGLMATRIXINDEXPOINTERARBPROC) (GLint size, GLenum type, GLsizei stride, const GLvoid *pointer);
 typedef void (APIENTRYP PFNGLBLITFRAMEBUFFEREXTPROC) (GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);
 typedef void (APIENTRYP PFNGLRENDERBUFFERSTORAGEMULTISAMPLEEXTPROC) (GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height);
+typedef void (APIENTRYP PFNGLRENDERBUFFERSTORAGEMULTISAMPLECOVERAGENVPROC) (GLenum target, GLsizei coverageSamples, GLsizei colorSamples, GLenum internalformat, GLsizei width, GLsizei height);
 #endif  // __EDG__
 
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