Add a "fork" of musl as //fusl.

This is musl verbatim at d5f8394f6ea9549607567bd92de12a2446c15614.

See http://www.musl-libc.org/.

R=kulakowski@chromium.org

Review URL: https://codereview.chromium.org/1573973002 .
diff --git a/fusl/src/process/posix_spawn_file_actions_destroy.c b/fusl/src/process/posix_spawn_file_actions_destroy.c
new file mode 100644
index 0000000..3251bab
--- /dev/null
+++ b/fusl/src/process/posix_spawn_file_actions_destroy.c
@@ -0,0 +1,14 @@
+#include <spawn.h>
+#include <stdlib.h>
+#include "fdop.h"
+
+int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *fa)
+{
+	struct fdop *op = fa->__actions, *next;
+	while (op) {
+		next = op->next;
+		free(op);
+		op = next;
+	}
+	return 0;
+}