diff --git a/Makefile b/Makefile
index 3267915..ef8cce7 100644
--- a/Makefile
+++ b/Makefile
@@ -221,7 +221,7 @@
 
 HOSTCC       = gcc
 HOSTCXX      = g++
-HOSTCFLAGS   = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer
 HOSTCXXFLAGS = -O2
 
 # Decide whether to build built-in, modular, or both.