buildgcc: Add coreboot toolchain version to iasl

Add the coreboot toolchain version to iasl's version output.

% ./xgcc/bin/iasl -v
Intel ACPI Component Architecture
ASL+ Optimizing Compiler version 20150619-64
Copyright (c) 2000 - 2015 Intel Corporation

coreboot toolchain v1.33 November 25th, 2015

This won't actually be checked until the next version of
iasl so that we don't have to rebuild again for no reason.

The buildgcc version was intentionally not incremented for
this minor change.

Change-Id: I03a1a777fdb84e34bfceb7b1eb43fffbc1f3a2fc
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12688
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

util/crossgcc/buildgcc

@@ -488,7 +488,7 @@ build_IASL() {
 	test $UNAME = "Darwin" && HOST="_APPLE"
 	test $UNAME = "FreeBSD" && HOST="_FreeBSD"
 	test $UNAME = "Cygwin" && HOST="_CYGWIN"
-	HOST="$HOST" OPT_CFLAGS="-O -D_FORTIFY_SOURCE=2" CFLAGS="$CFLAGS" $MAKE CC="$CC" iasl || touch $RDIR/.failed
+	HOST="$HOST" OPT_CFLAGS="-O -D_FORTIFY_SOURCE=2 -D COREBOOT_TOOLCHAIN_VERSION='\"coreboot toolchain v$CROSSGCC_VERSION $CROSSGCC_DATE\"' " CFLAGS="$CFLAGS" $MAKE CC="$CC" iasl || touch $RDIR/.failed
 	rm -f $DESTDIR$TARGETDIR/bin/iasl || touch $RDIR/.failed
 	cp bin/iasl $DESTDIR$TARGETDIR/bin || touch $RDIR/.failed
 }

util/crossgcc/patches/acpica-unix-20150619_iasl.patch

@@ -0,0 +1,12 @@
+diff -urN acpica-unix-20150619/source/compiler/asloptions.c acpica-unix-20150619/source/compiler/asloptions.c
+--- acpica-unix-20150619/source/compiler/asloptions.c   2015-06-19 08:56:19.000000000 -0600
++++ acpica-unix-20150619/source/compiler/asloptions.c 2015-12-08 10:44:58.816669240 -0700
+@@ -717,6 +717,7 @@
+         case '^':
+
+             printf (ACPI_COMMON_SIGNON (ASL_COMPILER_NAME));
++            printf ("%s\n", COREBOOT_TOOLCHAIN_VERSION);
+             exit (0);
+
+         case 'a':
+