re PR middle-end/53510 (OOM while compile some code)

re PR middle-end/53510 (OOM while compile some code)

	PR middle-end/53510
	* input.c (read_line): Use XRESIZEVEC instead of XNEWVEC
	to avoid leaking memory.  No need to handle memory allocation
	failure.  Double string_len on each reallocation instead of
	adding 2.
	* gcov.c (read_line): Likewise.

From-SVN: r187952