[gfortran] patch for TTYNAM function

[FX Coudert]

>>+#ifdef HAVE_STRING_H
>> #include <string.h>
>>+#endif
> 
> Why?

Because this file uses memset, which is located in string.h, and some 
other intrinsics sources in libgfortran protect it with an #ifdef. Is it 
adequate, or should we assume that string.h is always there?

>>+	  *name = __builtin_strdup (*name);
> 
> ...
> 
>>-  return malloc (*size);
>>+  return __builtin_malloc (*size);
> 
> Definitely not.
> 
> I'm not in favour of supporting pre-iso systems.  There are
> really just too many problems there.

OK. Commiting with strdup instead of __builtin_strdup and malloc instead 
of __builtin_malloc.

FX