diff --git a/configure.ac b/configure.ac
index 2dc566d..3a46fbd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,6 +24,12 @@ PKG_PROG_PKG_CONFIG
 
 PKG_CHECK_MODULES(FUSE, fuse)
 
+CFLAGS_WARN="$CFLAGS_WARN -Wall -Wextra -Werror -Wno-unused-parameter"
+CFLAGS_WARN="$CFLAGS_WARN -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes"
+CFLAGS_WARN="$CFLAGS_WARN -Waggregate-return -Wpointer-arith -Wshadow -Wwrite-strings"
+CFLAGS_WARN="$CFLAGS_WARN -Wcast-align -Wcast-qual"
+AC_SUBST(CFLAGS_WARN)
+
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([
 Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index 046150c..d38a059 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,9 +1,4 @@
 
-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
 
 ttynvt_SOURCES = \