Make systems with broken dynamic linkers happy.

stepmania/autoconf/m4/opengl.m4

@@ -7,12 +7,33 @@ AC_DEFUN(SM_OPENGL,
 	AC_CHECK_LIB(MesaGL, glPushMatrix, GL_LIBS=-lMesaGL)
     fi
 
-    if test -z "$GL_LIBS"; then
+    if test "$GL_LIBS" = ""; then
 	AC_CHECK_LIB(GL, glPushMatrix, GL_LIBS="-lGL")
     fi
 
+    # Some broken systems need us to link to X explicitly because
+    # the GL library needs it, instead of doing it automatically.
+    if test "$GL_LIBS" = ""; then
+	AC_PATH_X
+	AC_PATH_XTRA
+
+	oldLIBS=$LIBS
+	EXTRALIBS="$X_LIBS $X_EXTRA_LIBS $X_PRE_LIBS -lX11"
+	LIBS="$LIBS $EXTRALIBS"
+
+	if test "$enable_mesa" = "yes"; then
+	    AC_CHECK_LIB(MesaGL, glPushMatrix, GL_LIBS="-lMesaGL $EXTRALIBS")
+	fi
+	if test "$GL_LIBS" = ""; then
+	    AC_CHECK_LIB(GL, glPushMatrix, GL_LIBS="-lGL $EXTRALIBS")
+	fi
+	LIBS=$oldLIBS
+	oldLIBS=
+	EXTRALIBS=
+    fi
+
     AC_SUBST(GL_LIBS)
-    if test -z $GL_LIBS; then
+    if test "$GL_LIBS" = ""; then
 	AC_MSG_ERROR(["No OpenGL libraries could be found.  If you want
 to search for MesaGL, pass the "--enable-mesa" flag to configure.])
     fi