libtcc: new LIBTCCAPI tcc_set_options(TCCState*, const char*str)

This replaces       -> use instead:
-----------------------------------
- tcc_set_linker    -> tcc_set_options(s, "-Wl,...");
- tcc_set_warning   -> tcc_set_options(s, "-W...");
- tcc_enable_debug  -> tcc_set_options(s, "-g");

parse_args is moved to libtcc.c (now tcc_parse_args).

Also some cleanups:
- reorder TCCState members
- add some comments here and there
- do not use argv's directly, make string copies
- use const char* in tcc_set_linker
- tccpe: use fd instead of fp

tested with -D MEM_DEBUG: 0 bytes left

win32/tools/tiny_libmaker.c

@@ -79,7 +79,7 @@ int main(int argc, char **argv)
     ElfW(Sym) *sym;
     int i, fsize, iarg;
     char *buf, *shstr, *symtab = NULL, *strtab = NULL;
-    int symtabsize = 0, strtabsize = 0;
+    int symtabsize = 0;//, strtabsize = 0;
     char *anames = NULL;
     int *afpos = NULL;
     int istrlen, strpos = 0, fpos = 0, funccnt = 0, funcmax, hofs;
@@ -171,7 +171,7 @@ int main(int argc, char **argv)
                 if (!strcmp(shstr + shdr->sh_name, ".strtab"))
                 {
                     strtab = (char *)(buf + shdr->sh_offset);
-                    strtabsize = shdr->sh_size;
+                    //strtabsize = shdr->sh_size;
                 }
             }
         }