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

fusl/include/dlfcn.h

+#ifndef _DLFCN_H
+#define _DLFCN_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <features.h>
+
+#define RTLD_LAZY   1
+#define RTLD_NOW    2
+#define RTLD_NOLOAD 4
+#define RTLD_NODELETE 4096
+#define RTLD_GLOBAL 256
+#define RTLD_LOCAL  0
+
+#define RTLD_NEXT    ((void *)-1)
+#define RTLD_DEFAULT ((void *)0)
+
+#define RTLD_DI_LINKMAP 2
+
+int    dlclose(void *);
+char  *dlerror(void);
+void  *dlopen(const char *, int);
+void  *dlsym(void *__restrict, const char *__restrict);
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+typedef struct {
+        const char *dli_fname;
+        void *dli_fbase;
+        const char *dli_sname;
+        void *dli_saddr;
+} Dl_info;
+int dladdr(const void *, Dl_info *);
+int dlinfo(void *, int, void *);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif