linux: add -fvisibility=hidden to build flags

linux: add -fvisibility=hidden to build flags

We use this on OS X, so it shouldn't be harmful and it will fix a visibility
issue that came up in
  http://groups.google.com/group/chromium-dev/browse_thread/thread/800bda968bdc8f29

BUG=17943
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=30253

[Evan Martin, 2009-10-27 18:21:42]

http://codereview.chromium.org/332035/diff/1001/1003
File webkit/glue/plugins/test/npapi_test.cc (right):

http://codereview.chromium.org/332035/diff/1001/1003#newcode56
Line 56: #endif
Note that this is kinda premature, since this code doesn't yet run on Linux, but
it can't hurt to set the stage.

[Greg Spencer, 2009-10-27 18:25:48]

LGTM

[Evan Martin, 2009-10-27 18:27:52]

Will this break the o3d build?  How should/can I test?

[Greg Spencer, 2009-10-27 18:35:29]

AFAICT, this will not break the O3D build -- we don't build webkit, and our
common.gypi already has the hidden flag set, so no flags should change for
us.  If you'd like to test, you'll have to create an O3D client and patch in
your change and build using GYP, but I don't think it's likely to break
anything.

-Greg.

On Tue, Oct 27, 2009 at 11:27 AM, <evan@chromium.org> wrote:

> Will this break the o3d build?  How should/can I test?
>
>
> http://codereview.chromium.org/332035
>

[Mark Mentovai, 2009-10-27 18:39:39]

LGTM very much.  We've been using this on the Mac for a really long time.

On Linux, this might even reduce load (ld.so) time.

http://codereview.chromium.org/332035/diff/1001/1003
File webkit/glue/plugins/test/npapi_test.cc (right):

http://codereview.chromium.org/332035/diff/1001/1003#newcode52
Line 52: #if defined(OS_LINUX)
Can you make this || defined(OS_MACOSX) too?

http://codereview.chromium.org/332035/diff/1001/1004
File webkit/tools/npapi_layout_test_plugin/main.cpp (right):

http://codereview.chromium.org/332035/diff/1001/1004#newcode42
Line 42: #elif defined(__linux)
Same.

[Evan Martin, 2009-10-27 18:40:48]

Hm, since you've been using this on OS X, how has the layout test plugin been
working?

Maybe I should just make it conditional on GCC?

[Mark Mentovai, 2009-10-27 18:46:16]

I don't think we're doing the plugin tests on the Mac yet.

[Evan Martin, 2009-10-27 19:26:50]

Please re-review, had to rejigger it to make it compile on Windows.

[piman, 2009-10-27 19:40:42]

LGTM. Thanks a lot for doing this !

[piman, 2009-10-27 19:51:07]

Actually, I think this may break the shared library build. Maybe you want to
make that flag conditional ?

[Evan Martin, 2009-10-27 21:01:23]

updated with fix for shared; verified by re-gypping and seeing the flag go away

[piman, 2009-10-27 21:06:44]

LGTM