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

fusl/src/ctype/wcwidth.c

Index: fusl/src/ctype/wcwidth.c
diff --git a/fusl/src/ctype/wcwidth.c b/fusl/src/ctype/wcwidth.c
new file mode 100644
index 0000000000000000000000000000000000000000..49c40eea8cabfc6f1a0a30aafda9625e85b82611
--- /dev/null
+++ b/fusl/src/ctype/wcwidth.c
@@ -0,0 +1,29 @@
+#include <wchar.h>
+
+static const unsigned char table[] = {
+#include "nonspacing.h"
+};
+
+static const unsigned char wtable[] = {
+#include "wide.h"
+};
+
+int wcwidth(wchar_t wc)
+{
+	if (wc < 0xffU)
+		return (wc+1 & 0x7f) >= 0x21 ? 1 : wc ? -1 : 0;
+	if ((wc & 0xfffeffffU) < 0xfffe) {
+		if ((table[table[wc>>8]*32+((wc&255)>>3)]>>(wc&7))&1)
+			return 0;
+		if ((wtable[wtable[wc>>8]*32+((wc&255)>>3)]>>(wc&7))&1)
+			return 2;
+		return 1;
+	}
+	if ((wc & 0xfffe) == 0xfffe)
+		return -1;
+	if (wc-0x20000U < 0x20000)
+		return 2;
+	if (wc == 0xe0001 || wc-0xe0020U < 0x5f || wc-0xe0100 < 0xef)
+		return 0;
+	return 1;
+}