linux-sunxi: add patches for gcc5

The linux-sunxi 3.4 kernel could not be compiled with gcc5 (which
is standard in master now). Add two patches to make it compile again.

- Add missing compiler-gcc5.h
- Fix "multiple definition of `return_address'" errors

Open issue: All realtek wifi drivers fail to compile. Because of this
keep info to switch back to gcc4 in readme.

Signed-off-by: Jens Lucius <info@jenslucius.com>

recipes-kernel/linux/linux-sunxi/0002-use-static-inline-in-ARM-ftrace.patch

@@ -0,0 +1,50 @@
+From ef4fea130eeb70eff4f3a549fd3f6e9b11437550 Mon Sep 17 00:00:00 2001
+From: ZaneZam <cyxman@yahoo.com>
+Date: Thu, 26 Mar 2015 14:50:10 +0100
+Subject: [PATCH] arm: LLVMLinux: use static inline in ARM ftrace.h
+
+With compilers which follow the C99 standard (like modern versions of gcc and
+clang), "extern inline" does the wrong thing (emits code for an externally
+linkable version of the inline function). In this case using static inline
+and removing the NULL version of return_address in return_address.c does
+the right thing.
+
+Signed-off-by: Behan Webster <behanw@converseincode.com>
+Reviewed-by: Mark Charlebois <charlebm@gmail.com>
+
+source: http://www.serverphorums.com/read.php?12,880351,880351#msg-880351
+---
+ arch/arm/include/asm/ftrace.h    | 2 +-
+ arch/arm/kernel/return_address.c | 2 ++
+ 2 files changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
+index f89515a..2bb8cac 100644
+--- a/arch/arm/include/asm/ftrace.h
++++ b/arch/arm/include/asm/ftrace.h
+@@ -45,7 +45,7 @@ void *return_address(unsigned int);
+ 
+ #else
+ 
+-extern inline void *return_address(unsigned int level)
++static inline void *return_address(unsigned int level)
+ {
+ 	return NULL;
+ }
+diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c
+index f1aef84..49477f0 100644
+--- a/arch/arm/kernel/return_address.c
++++ b/arch/arm/kernel/return_address.c
+@@ -62,10 +62,12 @@ void *return_address(unsigned int level)
+ /* #warning "TODO: return_address should use unwind tables" */
+ #endif
+ 
++/*
+ void *return_address(unsigned int level)
+ {
+ 	return NULL;
+ }
++*/
+ 
+ #endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
+