diff --git a/configure.ac b/configure.ac
index c624b52e..db8dcdb1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -285,6 +285,7 @@ AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wnormalized=id], [CWFLAGS="$CWFLAGS -Wnormalize
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wnull-dereference], [CWFLAGS="$CWFLAGS -Wnull-dereference"])
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wpointer-arith], [CWFLAGS="$CWFLAGS -Wpointer-arith"])
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wredundant-decls], [CWFLAGS="$CWFLAGS -Wredundant-decls"])
+AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wshorten-64-to-32], [CWFLAGS="$CWFLAGS -Wshorten-64-to-32"])
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wstrict-prototypes], [CWFLAGS="$CWFLAGS -Wstrict-prototypes"])
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wswitch-enum], [CWFLAGS="$CWFLAGS -Wswitch-enum"])
 AX_CHECK_COMPILE_FLAG([$CWFLAGS -Wvariable-decl], [CWFLAGS="$CWFLAGS -Wvariable-decl"])