mutiples fix for _Generic

mutiples fix for _Generic

* check that _Generic don't match unsigned char * with char *
  this case is usefull as with -funsigned-char, 'char *' are unsigned

* change VT_LONG so it's now a qualifier

  VT_LONG are never use for code generation, but only durring parsing state,
  in _Generic we need to be able to make diference between
  'long' and 'long long'
  So VT_LONG is now use as a type qualifier, it's old behaviour is still
  here, but we can keep trace of what was a long and what wasn't

* add TOK_CLONG and TOK_CULONG

  tcc was directly converting value like '7171L' into TOK_CLLONG or
  TOK_CINT depending of the machine architecture.

  because of that, we was unable to make diference between a long and a
  long long, which doesn't work with _Generic.

  So now 7171L is a TOK_CLONG, and we can handle _Generic properly

* check that _Generic can make diference between long and long long

* uncomment "type match twice" as it should now pass tests on any platforms

* add inside_generic global

  the point of this variable is to use VT_LONG in comparaison only
  when we are evaluating a _Generic.
  problem is with my lastest patchs tcc can now make the diference between
  a 'long long' and a 'long', but in 64 bit stddef.h typedef uint64_t as
  typedef signed long long int int64_t and stdint.h as unsigned long int, so tcc
  break when stdint.h and stddef.h are include together.

  Another solution woud be to modifie include/stddef.h so it define uint64_t as
  unsigned long int when processor is 64 bit, but this could break some
  legacy code, so for now, VT_LONG are use only inside generc.

* check that _Generic parse first argument correctly

* check that _Generic evaluate correctly exresion like "f() / 2"