diff --git a/configure.ac b/configure.ac
index 80ee682a..7ca9d534 100644
--- a/configure.ac
+++ b/configure.ac
@@ -187,11 +187,11 @@ base_LIBS="$LIBS"
 dnl check for glut location
 AC_CHECK_HEADER(GL/glut.h)
 if test "x$ac_cv_header_GL_glut_h" = "xyes"; then
-    AC_DEFINE([GLUT_H], "GL/glut.h", [Define as glut.h include location])
+    AC_DEFINE([GLUT_H], <GL/glut.h>, [Define as glut.h include location])
 else
     AC_CHECK_HEADER(GLUT/glut.h)
     if test "x$ac_cv_header_GLUT_glut_h" = "xyes"; then
-        AC_DEFINE([GLUT_H], "GLUT/glut.h", [Define as glut.h include location])
+        AC_DEFINE([GLUT_H], <GLUT/glut.h>, [Define as glut.h include location])
     else
         echo "Neither GL/glut.h nor GLUT/glut.h found.  Cannot continue"
         exit