Fix and simplify handling of options for MSVC

[llunak]

These are various fixes (on top) of #506 .

[jrosdahl]

I'd appreciate it if you could submit "handle newlines on Windows properly" and "handle properly also stdout in addition to stderr" as separate PRs since they are independent.

[llunak]

I'd appreciate it if you could submit "handle newlines on Windows properly" and "handle properly also stdout in addition to stderr" as separate PRs since they are independent.

They are not, they both modify the block in ccache.cpp around line 950.

[jrosdahl]

They are not, they both modify the block in ccache.cpp around line 950.

I did not mean that the commits as currently written are independent, I meant that the fix and the feature are logically independent of "MSVC fixes". The first can be introduced separately to fix send_to_stderr on Windows. This point is quite minor and I'm OK with not doing that one separately if you think it's hard or tedious to do so. The second one however is a generic "we can now cache stdout for any compiler" feature, not an MSVC fix per se.

[rvogg]

The commit 60a6d2d breaks the correct behavior of ccache.
With export CCACHE_NOCPP2=1 the preprocessor output is written to stdout.

[llunak]

I did not mean that the commits as currently written are independent, I meant that the fix and the feature are logically independent of "MSVC fixes". The first can be introduced separately to fix send_to_stderr on Windows. This point is quite minor and I'm OK with not doing that one separately if you think it's hard or tedious to do so. The second one however is a generic "we can now cache stdout for any compiler" feature, not an MSVC fix per se.

Done in #962.

The commit 60a6d2d breaks the correct behavior of ccache. With export CCACHE_NOCPP2=1 the preprocessor output is written to stdout.

Fixed there.

[llunak]

I've separated these commits into more PRs, so this one is now only one commit.

It makes the code properly handle both -option and /option way of writing MSVC options, which also fixes several places where they weren't both listed properly. It is done by converting all /option arguments to -option (rather than listing both cases everywhere and risking mistakes), and if the handling gets to passing the argument as a file it gets changed back.