diff --git a/Makefile b/Makefile
index 9236c64..7d9acb8 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,8 @@ CFLAGS += -O2 -g -ggdb -c -std=gnu11 \
 
 LDFLAGS += -Wl,-z,now -Wl,-z,relro -pie -Wa,--noexecstack
 
-COMPILER_CLANG = $(shell $(CC) -v 2>&1 | grep version | head -n1 | egrep -o clang)
+COMPILER_CLANG = $(shell $(CC) -v 2>&1 | grep "clang version" | grep -o "clang")
+
 ifeq ($(COMPILER_CLANG),clang)
 	CFLAGS += -fblocks
 	LDFLAGS += -lBlocksRuntime
diff --git a/nsjail.c b/nsjail.c
index 6dbfc0c..5f125b6 100644
--- a/nsjail.c
+++ b/nsjail.c
@@ -115,6 +115,7 @@ static void nsjailListenMode(struct nsjconf_t *nsjconf)
 	if (listenfd == -1) {
 		return;
 	}
+	defer(close(listenfd));
 	for (;;) {
 		if (nsjailSigFatal > 0) {
 			subprocKillAll(nsjconf);