baremetal: build userland/ programs using baremetal path property instead of symlinks

Otherwise I'll go crazy with symlink action.

userland/c/exit0.c

@@ -0,0 +1,7 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#magic-failure-string */
+
+#include <stdlib.h>
+
+int main(void) {
+    exit(0);
+}