[RFC PATCH 3/4] sh: define __BIG_ENDIAN for math-emu

[Randy Dunlap]

The headers in include/math-emu/ test for __BYTE_ORDER == __BIG_ENDIAN
without checking to see if these macros are defined, so add
a define for __BIG_ENDIAN before pulling in these headers.

This placates these build warnings:

In file included from ../arch/sh/math-emu/math.c:23:
../include/math-emu/single.h:50:21: warning: "__BIG_ENDIAN" is not defined, evaluates to 0 [-Wundef]
   50 | #if __BYTE_ORDER == __BIG_ENDIAN
In file included from ../arch/sh/math-emu/math.c:24:
../include/math-emu/double.h:59:21: warning: "__BIG_ENDIAN" is not defined, evaluates to 0 [-Wundef]
   59 | #if __BYTE_ORDER == __BIG_ENDIAN

Fixes: 4b565680d163 ("sh: math-emu support")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: linux-sh@xxxxxxxxxxxxxxx
---
 arch/sh/math-emu/sfp-util.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20210528.orig/arch/sh/math-emu/sfp-util.h
+++ linux-next-20210528/arch/sh/math-emu/sfp-util.h
@@ -70,4 +70,4 @@
 
 #define __BYTE_ORDER __LITTLE_ENDIAN
 
-
+#define __BIG_ENDIAN 0