Match MSL_C (#8)

* match wstring.c

* match math_api.c, mbstring.c, mem.c and mem_funcs.c

* more progress

* build issues

* fix non-matching issues

* reorganise files

* match fdlibm (+ libc progress)

* fix jp build

* solved some non-matchings and progress

* removed types.h usage in libc

* match data and add missing delinks for jp

libs/c/include/mbstring.h

@@ -0,0 +1,19 @@
+#ifndef _C_MBSTRING_H
+#define _C_MBSTRING_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int mbtowc(wchar_t *pwc, const char *s, int n);
+int __mbtowc_noconv(wchar_t *pwc, const char *str, int n);
+int __wctomb_noconv(char *s, wchar_t wchar);
+size_t mbstowcs(wchar_t *pDest, const char *pSrc, size_t num);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif