buildgcc: Check exit status of `getopt`

We accidentally checked the status of `eval` instead.

Change-Id: I1ba258944184ed707ed1f176e528d8266656cb59
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/16680
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/util/crossgcc/buildgcc b/util/crossgcc/buildgcc
index af6cbe2..0c01546 100755
--- a/util/crossgcc/buildgcc
+++ b/util/crossgcc/buildgcc
@@ -691,14 +691,16 @@
 if [ "${getoptbrand}" = "getopt" ]; then
 	# Detected GNU getopt that supports long options.
 	args=$(getopt -l version,help,clean,directory:,bootstrap,platform:,languages:,package:,jobs:,destdir:,savetemps,scripting,ccache,supported:,urls,nocolor -o Vhcd:bp:l:P:j:D:tSys:un -- "$@")
+	getopt_ret=$?
 	eval set -- "$args"
 else
 	# Detected non-GNU getopt
 	args=$(getopt Vhcd:bp:l:P:j:D:tSys:un $*)
+	getopt_ret=$?
 	set -- $args
 fi
 
-if [ $? != 0 ]; then
+if [ $getopt_ret != 0 ]; then
 	myhelp
 	exit 1
 fi