[PATCH] Support gcc 6 for building

[Andi Kleen <andi@firstfloor.org>]

From: Andi Kleen <ak@linux.intel.com>

gcc recently switched to a new version number scheme, where every version
gets a new major version number. The current version is 5.x, the next 6.x, etc.

The gcc git repository trunk branch just switched to report 6.x for the next
major release.

This breaks the way Linux selects compiler-gccX.h based on the major
version. Every new version would require adding a new compiler-gccX.h file,
which wouldn't really scale.

Let's assume that future gccs are fairly compatible (they are unlikely
to break anything Linux is relying on). So we can just keep using
compiler-gcc5.h, and select any specific differences with #if.

Cc: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/linux/compiler-gcc.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index cdf13ca..9c9a4e4 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -104,7 +104,12 @@
 #define __gcc_header(x) #x
 #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
 #define gcc_header(x) _gcc_header(x)
-#include gcc_header(__GNUC__)
+#if __GNUC__ < 5
+#define __LINUX_GCC_VERSION __GNUC__
+#else
+#define __LINUX_GCC_VERSION 5
+#endif
+#include gcc_header(__LINUX_GCC_VERSION)
 
 #if !defined(__noclone)
 #define __noclone	/* not needed */
-- 
2.3.3