Fix unsafe compilation path in the wx configure script.

Index: wx/configure.in
===================================================================
--- otp_src_R15B.orig/lib/wx/configure.in
+++ otp_src_R15B/lib/wx/configure.in
@@ -234,18 +234,10 @@ if test X"$host_os" != X"win32" ; then
        	$as_unset ac_cv_header_GL_gl_h
        	AC_CHECK_HEADERS([GL/gl.h])
        	if test X"$ac_cv_header_GL_gl_h" != Xyes ; then
-	    AC_MSG_NOTICE(Checking for OpenGL headers in /usr/local)
-	    CPPFLAGS="-isystem /usr/local/include $saved_CPPFLAGS"
-	    $as_unset ac_cv_header_GL_gl_h
-	    AC_CHECK_HEADERS([GL/gl.h])
-	    if test X"$ac_cv_header_GL_gl_h" != Xyes ; then
 		AC_MSG_WARN([No OpenGL headers found, wx will NOT be usable])
 		CPPFLAGS="$saved_CPPFLAGS"
-	    else 
-	    	GL_LIBS="-L/usr/local/lib $GL_LIBS"
-	    fi
 	else 
-    	    GL_LIBS="-L/usr/X11R6/lib $GL_LIBS"
+    	    GL_LIBS="-L=/usr/X11R6/lib $GL_LIBS"
        	fi
     fi
 else