Ensure collect2 responds to intended commmand line options.

Ensure collect2 responds to intended commmand line options.

To ensure compatibility with the flags consumed by ld, some of the flags
needed by collect2 come from the command line and some are passed
in the COLLECT_GCC_OPTIONS.

Here we combine initial parses of both and then set the LTO mode accordingly.

2018-12-23  Iain Sandoe  <iain@sandoe.co.uk>

	* collect2.c (main): Combine flags from both the command line and
	COLLECT_GCC_OPTIONS to determine the set in force

From-SVN: r267369