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

fusl/src/conf/confstr.c

+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+
+size_t confstr(int name, char *buf, size_t len)
+{
+        const char *s = "";
+        if (!name) {
+                s = "/bin:/usr/bin";
+        } else if ((name&~4U)!=1 && name-_CS_POSIX_V6_ILP32_OFF32_CFLAGS>31U) {
+                errno = EINVAL;
+                return 0;
+        }
+        // snprintf is overkill but avoid wasting code size to implement
+        // this completely useless function and its truncation semantics
+        return snprintf(buf, len, "%s", s) + 1;
+}