Update xcompile to search for x86_64 toolchain.

This adds detection of x86_64 gcc toolchain (which buildgcc can build
if provided the option).

Change-Id: I8b12f3e705157741279c7347f4847fb50ccc2b0e
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/673
Reviewed-by: Rudolf Marek <r.marek@assembler.cz>
Tested-by: build bot (Jenkins)

util/xcompile/xcompile

@@ -36,14 +36,19 @@ done
 
 GCCPREFIX=invalid
 XGCCPATH=${1:-"`pwd`/util/crossgcc/xgcc/bin/"}
-echo '#XGCCPATH='${XGCCPATH}
+echo '# XGCCPATH='${XGCCPATH}
 TMPFILE=`mktemp /tmp/temp.XXXX 2>/dev/null || echo /tmp/temp.78gOIUGz`
 touch $TMPFILE
 
-# This should be a loop over all supported architectures
+# This loops over all supported architectures in TARCH
-TARCH=i386
+TARCH=('i386' 'x86_64')
 TWIDTH=32
-for gccprefixes in ${XGCCPATH}${TARCH}-elf- ${TARCH}-elf- ""; do
+for search_for in "${TARCH[@]}"; do
+	TARCH_SEARCH=("${TARCH_SEARCH[@]}" ${XGCCPATH}${search_for}-elf- ${search_for}-elf-)
+done
+echo '# TARCH_SEARCH='${TARCH_SEARCH[@]}
+
+for gccprefixes in "${TARCH_SEARCH[@]}" ""; do
 	if ! which ${gccprefixes}as 2>/dev/null >/dev/null; then
 		continue
 	fi
@@ -63,8 +68,8 @@ for gccprefixes in ${XGCCPATH}${TARCH}-elf- ${TARCH}-elf- ""; do
 		if [ ${TYPE##* } == "elf${TWIDTH}-${TARCH}" ]; then
 			GCCPREFIX=$gccprefixes
 			ASFLAGS=--32
-			CFLAGS="-m32 "
+			CFLAGS="-m32 -Wl,-b,elf32-i386 -Wl,-melf_i386 "
-			LDFLAGS="-b elf32-i386"
+			LDFLAGS="-b elf32-i386 -melf_i386"
 			break
 		fi
 	fi