build: add some more build-time warnings

diff --git a/m4/compiler_warnings.m4 b/m4/compiler_warnings.m4
index eeacfae..3037c58 100644 (file)
--- a/m4/compiler_warnings.m4
+++ b/m4/compiler_warnings.m4
@@ -11,7 +11,9 @@ if test "$GCC" = "yes" -a "$set_more_warnings" != "no"; then
                      -Wdeclaration-after-statement \
                      -Wfloat-equal -Wno-unused-parameter -Wno-sign-compare \
                      -fno-strict-aliasing -Wno-unused-but-set-variable \
-                     -Wundef; do
+                     -Wundef -Wimplicit-function-declaration \
+                     -Wpointer-arith -Winit-self \
+                     -Wmissing-include-dirs -Waggregate-return; do
                SAVE_CFLAGS="$CFLAGS"
                CFLAGS="$CFLAGS $option"
                AC_MSG_CHECKING([whether gcc understands $option])