diff --git a/scripts/libmakepkg/util/config.sh.in b/scripts/libmakepkg/util/config.sh.in
index e9bb7044..63f16d66 100644
--- a/scripts/libmakepkg/util/config.sh.in
+++ b/scripts/libmakepkg/util/config.sh.in
@@ -77,5 +77,8 @@ load_makepkg_config() {
 
 	source_makepkg_config "$MAKEPKG_CONF"
 
+	# prevent PKGBUILDs altering this directly
+	readonly -a BUILDENV
+
 	eval "$restore_envvars"
 }