Unrecognized command line parameters before -t are ignored on linux

[HampusAdolfsson]

I found a difference in how command line options are parsed on windows and linux, and am wondering if this is intentional.

On windows, any parameter that precedes the -t flag, and is not one of the global flags listed with -h, is passed on to the rest of the program. This means that targets and tool-specific flags can be passed before -t. On linux, any such parameters are ignored and never seen by the rest of the program.

Some examples:

# lists the command for 'foo.o' and 'bar.o' on windows but lists all commands on linux (equivalent to ninja -t commands)
ninja foo.o bar.o -t commands

# cleans generator outputs on windows but not on linux
ninja -g -t clean

The difference comes from here:

ninja/src/ninja.cc

Lines 1703 to 1705 in 931d990

	while (!options->tool &&
	(opt = getopt_long(*argc, *argv, "d:f:j:k:l:nt:vw:C:h", kLongOptions,
	NULL)) != -1) {

Ninja's own implementation of getopt_long appears to eagerly reorder argv, but the glibc(?) implementation appears to only do so when it is done processing the list. Thus if the loop is exited early because a tool was given, argv is left unmodified and optind simply points to the first parameter after the tool name.