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

fusl/src/locale/newlocale.c

Index: fusl/src/locale/newlocale.c
diff --git a/fusl/src/locale/newlocale.c b/fusl/src/locale/newlocale.c
new file mode 100644
index 0000000000000000000000000000000000000000..f50bbe9132df39445c642ea3215428b4b2b960d5
--- /dev/null
+++ b/fusl/src/locale/newlocale.c
@@ -0,0 +1,49 @@
+#include <stdlib.h>
+#include <string.h>
+#include "locale_impl.h"
+#include "libc.h"
+
+int __loc_is_allocated(locale_t loc)
+{
+	return loc && loc != C_LOCALE && loc != UTF8_LOCALE;
+}
+
+locale_t __newlocale(int mask, const char *name, locale_t loc)
+{
+	int i, j;
+	struct __locale_struct tmp;
+	const struct __locale_map *lm;
+
+	/* For locales with allocated storage, modify in-place. */
+	if (__loc_is_allocated(loc)) {
+		for (i=0; i<LC_ALL; i++)
+			if (mask & (1<<i))
+				loc->cat[i] = __get_locale(i, name);
+		return loc;
+	}
+
+	/* Otherwise, build a temporary locale object, which will only
+	 * be instantiated in allocated storage if it does not match
+	 * one of the built-in static locales. This makes the common
+	 * usage case for newlocale, getting a C locale with predictable
+	 * behavior, very fast, and more importantly, fail-safe. */
+	for (j=i=0; i<LC_ALL; i++) {
+		if (loc && !(mask & (1<<i)))
+			lm = loc->cat[i];
+		else
+			lm = __get_locale(i, mask & (1<<i) ? name : "");
+		if (lm) j++;
+		tmp.cat[i] = lm;
+	}
+
+	if (!j)
+		return C_LOCALE;
+	if (j==1 && tmp.cat[LC_CTYPE]==&__c_dot_utf8)
+		return UTF8_LOCALE;
+
+	if ((loc = malloc(sizeof *loc))) *loc = tmp;
+
+	return loc;
+}
+
+weak_alias(__newlocale, newlocale);