meta: move photon/libc to root

libc/stdio/vfprintf.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include "__printf.h"
+
+static void _out_file(struct __printf_backend *bk, char ch)
+{
+    FILE *fp = bk->arg;
+    if (ch) {
+        fputc(ch, fp);
+    }
+}
+
+int vfprintf(FILE *fp, const char *restrict format, va_list arg)
+{
+    struct __printf_backend bk = {};
+    bk.out = _out_file;
+    bk.arg = fp;
+
+    return __xprintf(&bk, format, arg);
+}