Require gcc 4.8 for debug fission

GCC didn't officially add -gsplit-dwarf until version 4.8

I tested with gcc 4.8 and then believed the internet when it said 4.7 had support. Someone was wrong on the internet, inconceivable!

Confirmed not supported on 4.7 via GCC release notes at
http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Debugging-Options.html#Debugging-Options

Confirmed supported on 4.8 via GCC release notes at
http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Debugging-Options.html#Debugging-Options

Issue reported by sigbjornf@opera.com

BUG=352046
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=257861

[mithro-old, 2014-03-18 14:01:56]

Hi,

Fixing an issue reported by sof about his build failing on gcc 4.7

Tim

[Nico, 2014-03-18 14:02:44]

lgtm

[mithro-old, 2014-03-18 14:04:27]

The CQ bit was checked by mithro@mithis.com

[commit-bot: I haz the power, 2014-03-18 14:05:16]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mithro@mithis.com/203133003/1

[commit-bot: I haz the power, 2014-03-18 16:03:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-18 16:03:53]

Retried try job too often on win_rel for step(s) app_list_unittests,
ash_unittests, aura_unittests, cacheinvalidation_unittests, cc_unittests,
check_deps, check_deps2git, chrome_elf_unittests, chromedriver_unittests,
components_unittests, compositor_unittests, content_browsertests,
content_unittests, crypto_unittests, events_unittests, gfx_unittests,
google_apis_unittests, gpu_unittests, installer_util_unittests, ipc_tests,
jingle_unittests, media_unittests, mini_installer_test, nacl_integration,
ppapi_unittests, printing_unittests, remoting_unittests, sql_unittests,
sync_integration_tests, sync_unit_tests, telemetry_perf_unittests,
telemetry_unittests, views_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[mithro-old, 2014-03-18 16:05:27]

The CQ bit was checked by mithro@mithis.com

[commit-bot: I haz the power, 2014-03-18 16:07:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mithro@mithis.com/203133003/1

[commit-bot: I haz the power, 2014-03-18 20:47:50]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-18 20:47:50]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[mithro-old, 2014-03-19 01:28:50]

The CQ bit was checked by mithro@mithis.com

[commit-bot: I haz the power, 2014-03-19 01:30:05]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mithro@mithis.com/203133003/1

[commit-bot: I haz the power, 2014-03-19 06:06:01]

Change committed as 257861

[dshwang, 2014-03-19 10:33:19]

Hi, can I ask a question?

Are you working on distributed build system? After your debug build
optimization, icecc debug build was broken.

FAILED: c++ -MMD -MF
obj/third_party/angle/src/compiler/preprocessor/preprocessor.MacroExpander.o.d
/* many options /*
obj/third_party/angle/src/compiler/preprocessor/preprocessor.MacroExpander.o
g++: error trying to exec 'objcopy': execvp: No such file or directory

I guess icecc cannot deal with objcopy, so I filed icecc bug;
https://github.com/icecc/icecream/issues/86
anyway, I'm curious that others are in trouble like me, and what is the best
solution for my problem.

[Nico, 2014-03-19 10:37:08]

On 2014/03/19 10:33:19, dshwang wrote:
> Hi, can I ask a question?
> 
> Are you working on distributed build system? After your debug build
> optimization, icecc debug build was broken.
> 
> FAILED: c++ -MMD -MF
> obj/third_party/angle/src/compiler/preprocessor/preprocessor.MacroExpander.o.d
> /* many options /*
> obj/third_party/angle/src/compiler/preprocessor/preprocessor.MacroExpander.o
> g++: error trying to exec 'objcopy': execvp: No such file or directory
> 
> I guess icecc cannot deal with objcopy, so I filed icecc bug;
> https://github.com/icecc/icecream/issues/86
> anyway, I'm curious that others are in trouble like me, and what is the best
> solution for my problem.

You can set GYP_DEFINES=binutils_version=0 to disable fission. Note that using
fission will make linking two to three times as fast, so you might instead
consider not using icecc until the bug in icecc is fixed. (You'll have slower
full builds, but much faster incremental builds. At least I do incremental
builds much more often than full builds.)