diff --git a/share/mk/bsd.compat.mk b/share/mk/bsd.compat.mk
--- a/share/mk/bsd.compat.mk
+++ b/share/mk/bsd.compat.mk
@@ -87,7 +87,7 @@
 # In the program linking case, select LIBCOMPAT
 .if defined(NEED_COMPAT)
 .ifndef HAS_COMPAT
-.warning NEED_COMPAT defined, but no LIBCOMPAT is available (COMPAT_ARCH == ${COMPAT_ARCH})
+.error NEED_COMPAT defined, but no LIBCOMPAT is available (COMPAT_ARCH == ${COMPAT_ARCH})
 .elif !${HAS_COMPAT:M${NEED_COMPAT}} && ${NEED_COMPAT} != "any"
 .error NEED_COMPAT (${NEED_COMPAT}) defined, but not in HAS_COMPAT (${HAS_COMPAT})
 .elif ${NEED_COMPAT} == "any"