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

fusl/src/passwd/getgrent.c

+#include "pwf.h"
+
+static FILE *f;
+static char *line, **mem;
+static struct group gr;
+
+void setgrent()
+{
+        if (f) fclose(f);
+        f = 0;
+}
+
+weak_alias(setgrent, endgrent);
+
+struct group *getgrent()
+{
+        struct group *res;
+        size_t size=0, nmem=0;
+        if (!f) f = fopen("/etc/group", "rbe");
+        if (!f) return 0;
+        __getgrent_a(f, &gr, &line, &size, &mem, &nmem, &res);
+        return res;
+}
+
+struct group *getgrgid(gid_t gid)
+{
+        struct group *res;
+        size_t size=0, nmem=0;
+        __getgr_a(0, gid, &gr, &line, &size, &mem, &nmem, &res);
+        return res;
+}
+
+struct group *getgrnam(const char *name)
+{
+        struct group *res;
+        size_t size=0, nmem=0;
+        __getgr_a(name, 0, &gr, &line, &size, &mem, &nmem, &res);
+        return res;
+}