diff --git a/auto/src/glew_head.c b/auto/src/glew_head.c
index 80200d1..4b98cd7 100644
--- a/auto/src/glew_head.c
+++ b/auto/src/glew_head.c
@@ -193,6 +193,7 @@ void* NSGLGetProcAddress (const GLubyte *name)
  * GLEW, just like OpenGL or GLU, does not rely on the standard C library.
  * These functions implement the functionality required in this file.
  */
+
 static GLuint _glewStrLen (const GLubyte* s)
 {
   GLuint i=0;
@@ -209,6 +210,17 @@ static GLuint _glewStrCLen (const GLubyte* s, GLubyte c)
   return (s[i] == '\0' || s[i] == c) ? i : 0;
 }
 
+static GLubyte *_glewStrDup (const GLubyte *s)
+{
+    int n = _glewStrLen(s) + 1;
+    GLubyte *dup = malloc(n);
+    if (dup)
+    {
+        strcpy((char *) dup, (const char *) s);
+    }
+    return dup;
+}
+
 static GLboolean _glewStrSame (const GLubyte* a, const GLubyte* b, GLuint n)
 {
   GLuint i=0;
diff --git a/auto/src/glew_init_gl.c b/auto/src/glew_init_gl.c
index c4548ad..890574b 100644
--- a/auto/src/glew_init_gl.c
+++ b/auto/src/glew_init_gl.c
@@ -140,7 +140,7 @@ GLenum GLEWAPIENTRY glewContextInit (GLEW_CONTEXT_ARG_DEF_LIST)
   }
   else
   {
-    const char *ext;
+    const GLubyte *ext;
     char *begin;
     char *end;
     char *i;
@@ -151,8 +151,8 @@ GLenum GLEWAPIENTRY glewContextInit (GLEW_CONTEXT_ARG_DEF_LIST)
 
     if (ext)
     {
-      begin = strdup(ext);
-      end = begin + strlen(begin);
+      begin = (char *) _glewStrDup(ext);
+      end = begin + _glewStrLen((GLubyte *) begin);
       for (i=begin; i<end; i = j + 1)
       {
         i = _glewNextNonSpace(i);