diff --git a/src/Makefile.am b/src/Makefile.am
index c1780f0..046150c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,8 @@
 
-CFLAGS_WARN = -Wall -Wextra -Werror -Wno-unused-parameter
+CFLAGS_WARN  = -Wall -Wextra -Werror -Wno-unused-parameter
+CFLAGS_WARN += -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes
+CFLAGS_WARN += -Waggregate-return -Wpointer-arith -Wshadow -Wwrite-strings
+CFLAGS_WARN += -Wcast-align -Wcast-qual
 
 bin_PROGRAMS = ttynvt