diff --git a/configure.in b/configure.in
index 2efba352f..d9013742b 100644
--- a/configure.in
+++ b/configure.in
@@ -11,6 +11,7 @@ AC_SUBST(CANONICAL_HOST)
 
 dnl Checks for programs.
 AC_PROG_CC
+
 dnl AC_KRB_PROG_YACC
 AC_PROG_YACC
 AC_PROG_LEX
@@ -18,6 +19,10 @@ AC_PROG_RANLIB
 AC_PROG_AWK
 AC_LN_S
 
+if test "$GCC" = "yes"; then
+  WFLAGS="-Wall -Wno-unused -Wconversion -Wmissing-prototypes -Wredundant-decls"
+fi
+AC_SUBST(WFLAGS)
 CFLAGS="-g"
 
 berkeley_db=db