multilib_header: Update wrapper to handle arm 32/64 bit

Having arm 32/64 bit headers coexisting turns out to be tricky. Unfortunately
our wrapper works using wordsize.h and this differs on arm so we can't use it.

Therefore replicate the logic here for arm. I did look into writing our
own wordsize.h but we also need to remap kernel headers on arm and
since wordsize.h comes from libc, that doesn't work for kernel headers.

(From OE-Core rev: 141dc7136c9c62da1d30132df4b3244fe6d8898d)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/multilib_header.bbclass

@@ -13,13 +13,9 @@ oe_multilib_header() {
 		;;
 	*)
 	esac
-        # We use
-        # For ARM: We don't support multilib builds.
         # For MIPS: "n32" is a special case, which needs to be
         # distinct from both 64-bit and 32-bit.
         case ${TARGET_ARCH} in
-        arm*)   return
-                ;;
         mips*)  case "${MIPSPKGSFX_ABI}" in
                 "-n32")
                        ident=n32   
@@ -31,9 +27,6 @@ oe_multilib_header() {
                 ;;
         *)      ident=${SITEINFO_BITS}
         esac
-	if echo ${TARGET_ARCH} | grep -q arm; then
-	    return
-	fi
 	for each_header in "$@" ; do
 	   if [ ! -f "${D}/${includedir}/$each_header" ]; then
 	      bberror "oe_multilib_header: Unable to find header $each_header."

scripts/multilib_header_wrapper.h

@@ -21,11 +21,23 @@
  * 
  */
 
-#include <bits/wordsize.h>
 
-#ifdef __WORDSIZE
+#if defined (__arm__)
+#define __MHWORDSIZE			32
+#elif defined (__aarch64__) && defined ( __LP64__)
+#define __MHWORDSIZE			64
+#elif defined (__aarch64__)
+#define __MHWORDSIZE			32
+#else
+#include <bits/wordsize.h>
+#if defined (__WORDSIZE)
+#define __MHWORDSIZE			__WORDSIZE
+#else
+#error "__WORDSIZE is not defined"
+#endif
+#endif
 
-#if __WORDSIZE == 32
+#if __MHWORDSIZE == 32
 
 #ifdef _MIPS_SIM
 
@@ -41,15 +53,9 @@
 #include <ENTER_HEADER_FILENAME_HERE-32.h>
 #endif
 
-#elif __WORDSIZE == 64
+#elif __MHWORDSIZE == 64
 #include <ENTER_HEADER_FILENAME_HERE-64.h>
 #else
 #error "Unknown __WORDSIZE detected"
 #endif /* matches #if __WORDSIZE == 32 */
-
-#else /* __WORDSIZE is not defined */
-
-#error "__WORDSIZE is not defined"
-
-#endif