testing/*:update config guess for loongarch64

testing/liblinbox/APKBUILD

@@ -24,6 +24,11 @@ source="https://github.com/linbox-team/linbox/releases/download/v$pkgver/linbox-
 subpackages="$pkgname-static $pkgname-dev $pkgname-doc"
 builddir="$srcdir/linbox-$pkgver"
 
+prepare() {
+       default_prepare
+       update_config_sub
+}
+
 build() {
 	export CXXFLAGS="${CXXFLAGS/-Os/-O3}" # gotta go fast