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

fusl/src/locale/strfmon.c

+#include <stdio.h>
+#include <ctype.h>
+#include <stdarg.h>
+#include <monetary.h>
+#include <errno.h>
+#include "locale_impl.h"
+
+static ssize_t vstrfmon_l(char *s, size_t n, locale_t loc, const char *fmt, va_list ap)
+{
+        size_t l;
+        double x;
+        int fill, nogrp, negpar, nosym, left, intl;
+        int lp, rp, w, fw;
+        char *s0=s;
+        for (; n && *fmt; ) {
+                if (*fmt != '%') {
+                literal:
+                        *s++ = *fmt++;
+                        n--;
+                        continue;
+                }
+                fmt++;
+                if (*fmt == '%') goto literal;
+
+                fill = ' ';
+                nogrp = 0;
+                negpar = 0;
+                nosym = 0;
+                left = 0;
+                for (; ; fmt++) {
+                        switch (*fmt) {
+                        case '=':
+                                fill = *++fmt;
+                                continue;
+                        case '^':
+                                nogrp = 1;
+                                continue;
+                        case '(':
+                                negpar = 1;
+                        case '+':
+                                continue;
+                        case '!':
+                                nosym = 1;
+                                continue;
+                        case '-':
+                                left = 1;
+                                continue;
+                        }
+                        break;
+                }
+
+                for (fw=0; isdigit(*fmt); fmt++)
+                        fw = 10*fw + (*fmt-'0');
+                lp = 0;
+                rp = 2;
+                if (*fmt=='#') for (lp=0, fmt++; isdigit(*fmt); fmt++)
+                        lp = 10*lp + (*fmt-'0');
+                if (*fmt=='.') for (rp=0, fmt++; isdigit(*fmt); fmt++)
+                        rp = 10*rp + (*fmt-'0');
+
+                intl = *fmt++ == 'i';
+
+                w = lp + 1 + rp;
+                if (!left && fw>w) w = fw;
+
+                x = va_arg(ap, double);
+                l = snprintf(s, n, "%*.*f", w, rp, x);
+                if (l >= n) {
+                        errno = E2BIG;
+                        return -1;
+                }
+                s += l;
+                n -= l;
+        }
+        return s-s0;
+}
+
+ssize_t strfmon_l(char *restrict s, size_t n, locale_t loc, const char *restrict fmt, ...)
+{
+        va_list ap;
+        ssize_t ret;
+
+        va_start(ap, fmt);
+        ret = vstrfmon_l(s, n, loc, fmt, ap);
+        va_end(ap);
+
+        return ret;
+}
+
+
+ssize_t strfmon(char *restrict s, size_t n, const char *restrict fmt, ...)
+{
+        va_list ap;
+        ssize_t ret;
+
+        va_start(ap, fmt);
+        ret = vstrfmon_l(s, n, CURRENT_LOCALE, fmt, ap);
+        va_end(ap);
+
+        return ret;
+}