[trivial] Add .DSYM to .gitignore

[fanquake]

Add debug symbols to .gitignore

[laanwj]

What OS is this for?

[btcdrak]

This is platform specific (OSX) and should be in your local global gitignore.

[laanwj]

@btcdrak I think we have more OS-specific stuff in there, .e.g DS_store and *.exe. I think the criterion should be whether the file is generated while following our supported build process.
If it is, it should be in our .gitignore.
If not, and it is part of some IDE or other user specific tool, it belongs in that user's gitignore.

Apart from that, at some point in our we should encourage in our build documentation doing out-of-tree builds so that it is no longer an issue.

[sipa]

@laanwj That sounds like a good criterion.

@fanquake Can you comment?

[theuni]

ACK @laanwj's comment.

[fanquake]

.DSYM are generated when running valgrind on OS X

[laanwj]

I'd say valgrind fits squarely into the 'other tools' category, it's not something we ever launch from the build system.