Force erroneous inclusions of compiler-*.h files to be errors

Replace worthless comments with actual preprocessor errors when including
the wrong versions of the compiler.h files.

[akpm@linux-foundation.org: make it work]
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
index a9e2863..2d8c0f4 100644
--- a/include/linux/compiler-gcc3.h
+++ b/include/linux/compiler-gcc3.h
@@ -1,4 +1,6 @@
-/* Never include this file directly.  Include <linux/compiler.h> instead.  */
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
+#endif
 
 /* These definitions are for GCC v3.x.  */
 #include <linux/compiler-gcc.h>