remove INT_MAX limit on the n argument to snprintf/swprintf

this was a POSIX requirement that was always in conflict with ISO C,
which specified a well-defined behavior for snprintf and swprintf so
long as the actual number of bytes/characters produced did not exceed
INT_MAX.

I originally raised this conflict for snprintf with the Austin Group
as tracker issue 761, which was never resolved. it was later reported
again as issue 1219, and as a result the conflicting requirement has
been removed.

the corresponding issue with swprintf does not seem to have been
addressed, but as the same reasoning applies to it, I am removing the
limitation on n for swprintf as well.

src/stdio/vsnprintf.c

@@ -45,11 +45,6 @@ int vsnprintf(char *restrict s, size_t n, const char *restrict fmt, va_list ap)
 		.cookie = &c,
 	};
 
-	if (n > INT_MAX) {
-		errno = EOVERFLOW;
-		return -1;
-	}
-
 	*c.s = 0;
 	return vfprintf(&f, fmt, ap);
 }

src/stdio/vswprintf.c

@@ -51,9 +51,6 @@ int vswprintf(wchar_t *restrict s, size_t n, const wchar_t *restrict fmt, va_lis
 
 	if (!n) {
 		return -1;
-	} else if (n > INT_MAX) {
-		errno = EOVERFLOW;
-		return -1;
 	}
 	r = vfwprintf(&f, fmt, ap);
 	sw_write(&f, 0, 0);