diff --git a/src/syscall/mkerrors.sh b/src/syscall/mkerrors.sh
index e833b50349..ddd55332ef 100755
--- a/src/syscall/mkerrors.sh
+++ b/src/syscall/mkerrors.sh
@@ -342,7 +342,7 @@ errors=$(
 signals=$(
 	echo '#include <signal.h>' | $CC -x c - -E -dM $ccflags |
 	awk '$1=="#define" && $2 ~ /^SIG[A-Z0-9]+$/ { print $2 }' |
-	grep -Ev 'SIGSTKSIZE|SIGSTKSZ|SIGRT' |
+	grep -v 'SIGSTKSIZE\|SIGSTKSZ\|SIGRT' |
 	sort
 )
 
@@ -352,7 +352,7 @@ echo '#include <errno.h>' | $CC -x c - -E -dM $ccflags |
 	sort >_error.grep
 echo '#include <signal.h>' | $CC -x c - -E -dM $ccflags |
 	awk '$1=="#define" && $2 ~ /^SIG[A-Z0-9]+$/ { print "^\t" $2 "[ \t]*=" }' |
-	grep -Ev 'SIGSTKSIZE|SIGSTKSZ|SIGRT' |
+	grep -v 'SIGSTKSIZE\|SIGSTKSZ\|SIGRT' |
 	sort >_signal.grep
 
 echo '// mkerrors.sh' "$@"