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

fusl/src/linux/cache.c

Index: fusl/src/linux/cache.c
diff --git a/fusl/src/linux/cache.c b/fusl/src/linux/cache.c
new file mode 100644
index 0000000000000000000000000000000000000000..3f0abc7caf16ec27697c2c0b4c050d0d17fa0a8e
--- /dev/null
+++ b/fusl/src/linux/cache.c
@@ -0,0 +1,18 @@
+#include "syscall.h"
+#include "libc.h"
+
+#ifdef SYS_cacheflush
+int _flush_cache(void *addr, int len, int op)
+{
+	return syscall(SYS_cacheflush, addr, len, op);
+}
+weak_alias(_flush_cache, cacheflush);
+#endif
+
+#ifdef SYS_cachectl
+int __cachectl(void *addr, int len, int op)
+{
+	return syscall(SYS_cachectl, addr, len, op);
+}
+weak_alias(__cachectl, cachectl);
+#endif