Patch to assembler to strip LOCK prefix.

The lock prefix is usually stripped by passing to the compiler -Wa,momit-lock-prefix=yes via EXTRA_CFLAGS. However I couldn't find a way to get buildroot to pass CFLAGS/EXTRA_CFLAGS around.

I tried using BR2_TARGET_OPTIMIZATION, and creating a new processor type but the flag kept stripping it out. I found the most reliable way to achieve the behavior was to make stripping the LOCK prefix the assembler's default behavior, hence the patch

---
 .../galileo/patches/binutils/2.25/default-lock-prefix.patch   | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 board/intel/galileo/patches/binutils/2.25/default-lock-prefix.patch

new file mode 100644
index 0000000..7814ae4
@@ -0,0 +1,11 @@
+--- a/gas/config/tc-i386.orig	2015-07-24 15:54:51.359080778 +0100
++++ b/gas/config/tc-i386.c	2015-07-24 15:54:59.692192247 +0100
+@@ -545,7 +545,7 @@ static int allow_index_reg = 0;
+ 
+ /* 1 if the assembler should ignore LOCK prefix, even if it was
+    specified explicitly.  */
+-static int omit_lock_prefix = 0;
++static int omit_lock_prefix = 1;
+ 
+ static enum check_kind
+   {

2.1.0