diff --git a/auto/bin/filter_gl_ext.sh b/auto/bin/filter_gl_ext.sh
index 2aa58c4..fa2a667 100755
--- a/auto/bin/filter_gl_ext.sh
+++ b/auto/bin/filter_gl_ext.sh
@@ -317,19 +317,19 @@ EOT
 # add typedef to GL_AMD_debug_output
 # parse_spec.pl can't parse typedefs from New Types section, but ought to
     cat >> $1/GL_AMD_debug_output <<EOT
-	typedef void (APIENTRY *GLDEBUGPROCAMD)(GLuint id, GLenum category, GLenum severity, GLsizei length, const GLchar* message, GLvoid* userParam)
+	typedef void (APIENTRY *GLDEBUGPROCAMD)(GLuint id, GLenum category, GLenum severity, GLsizei length, const GLchar* message, void* userParam)
 EOT
 
 # add typedef to GL_ARB_debug_output
 # parse_spec.pl can't parse typedefs from New Types section, but ought to
     cat >> $1/GL_ARB_debug_output <<EOT
-	typedef void (APIENTRY *GLDEBUGPROCARB)(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, GLvoid* userParam)
+	typedef void (APIENTRY *GLDEBUGPROCARB)(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam)
 EOT
 
 # add typedef to GL_KHR_debug
 # parse_spec.pl can't parse typedefs from New Types section, but ought to
     cat >> $1/GL_KHR_debug <<EOT
-	typedef void (APIENTRY *GLDEBUGPROC)(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, GLvoid* userParam)
+	typedef void (APIENTRY *GLDEBUGPROC)(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam)
 EOT
 
 # Remove glGetPointerv from GL_KHR_debug