diff --git a/Makefile.target b/Makefile.target
index d02d896..91967ec 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -73,7 +73,7 @@ endif
 PROGS=$(QEMU_PROG)
 
 # We require -O2 to avoid the stack setup prologue in EXIT_TB
-OP_CFLAGS := -Wall -Wundef -O2 -g -fno-strict-aliasing
+OP_CFLAGS := -Wall -Wundef -Wendif-labels -O2 -g -fno-strict-aliasing
 
 # cc-option
 # Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
diff --git a/configure b/configure
index 1da42a1..365e8ad 100755
--- a/configure
+++ b/configure
@@ -346,7 +346,7 @@ for opt do
 done
 
 # default flags for all hosts
-CFLAGS="$CFLAGS -Wall -Wundef -O2 -g -fno-strict-aliasing"
+CFLAGS="$CFLAGS -Wall -Wundef -Wendif-labels -O2 -g -fno-strict-aliasing"
 LDFLAGS="$LDFLAGS -g"
 if test "$werror" = "yes" ; then
 CFLAGS="$CFLAGS -Werror"