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

fusl/src/string/strdup.c

Index: fusl/src/string/strdup.c
diff --git a/fusl/src/string/strdup.c b/fusl/src/string/strdup.c
new file mode 100644
index 0000000000000000000000000000000000000000..dd5f80c1c39d20ea3d2f2e1393ebb081de3c2632
--- /dev/null
+++ b/fusl/src/string/strdup.c
@@ -0,0 +1,13 @@
+#include <stdlib.h>
+#include <string.h>
+#include "libc.h"
+
+char *__strdup(const char *s)
+{
+	size_t l = strlen(s);
+	char *d = malloc(l+1);
+	if (!d) return NULL;
+	return memcpy(d, s, l+1);
+}
+
+weak_alias(__strdup, strdup);