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

fusl/src/stdio/fgetws.c

Index: fusl/src/stdio/fgetws.c
diff --git a/fusl/src/stdio/fgetws.c b/fusl/src/stdio/fgetws.c
new file mode 100644
index 0000000000000000000000000000000000000000..195cb4355a14b10b05b0b50cf293456b5b7b4f75
--- /dev/null
+++ b/fusl/src/stdio/fgetws.c
@@ -0,0 +1,28 @@
+#include "stdio_impl.h"
+#include <wchar.h>
+
+wint_t __fgetwc_unlocked(FILE *);
+
+wchar_t *fgetws(wchar_t *restrict s, int n, FILE *restrict f)
+{
+	wchar_t *p = s;
+
+	if (!n--) return s;
+
+	FLOCK(f);
+
+	for (; n; n--) {
+		wint_t c = __fgetwc_unlocked(f);
+		if (c == WEOF) break;
+		*p++ = c;
+		if (c == '\n') break;
+	}
+	*p = 0;
+	if (ferror(f)) p = s;
+
+	FUNLOCK(f);
+
+	return (p == s) ? NULL : s;
+}
+
+weak_alias(fgetws, fgetws_unlocked);