Add helper comment for icecc users.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index e94ed2c8bdd7b9051dd05172a1c897765b699e28..853457f7fd64e922992d45505bdcfef0ca26eefb 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -170,6 +170,9 @@
         'use_goma%': 0,
         'gomadir%': '',
 
+        # When using icecc, we cannot use some build flags. e.g. debug fission, -B cflags.

[Lei Zhang, 2014/04/25 07:34:21]

How about:

Set to 1 when using icecc to avoid incompatible build flags.
e.g. ...

+        'use_icecc%': 0,
+
         # The system root for cross-compiles. Default: none.
         'sysroot%': '',
         'chroot_cmd%': '',
@@ -262,6 +265,7 @@
       'android_webview_build%': '<(android_webview_build)',
       'use_goma%': '<(use_goma)',
       'gomadir%': '<(gomadir)',
+      'use_icecc%': '<(use_icecc)',
       'enable_app_list%': '<(enable_app_list)',
       'use_default_render_theme%': '<(use_default_render_theme)',
       'buildtype%': '<(buildtype)',
@@ -744,6 +748,12 @@
           'linux_use_bundled_binutils%': 0,
         }],
 
+        # icecc cannot distribute jobs with -B.
+        # https://github.com/icecc/icecream/commit/b2ce5b9cc4bd1900f55c3684214e409fa81e7a92
+        ['use_icecc==1', {
+          'linux_use_bundled_binutils%': 0,
+        }],
+
         # linux_use_gold_flags: whether to use build flags that rely on gold.
         # On by default for x64 Linux.  Temporarily off for ChromeOS as
         # it failed on a buildbot.
@@ -1044,6 +1054,7 @@
     'proprietary_codecs%': '<(proprietary_codecs)',
     'use_goma%': '<(use_goma)',
     'gomadir%': '<(gomadir)',
+    'use_icecc%': '<(use_icecc)',
 
     # Use system protobuf instead of bundled one.
     'use_system_protobuf%': 0,
@@ -3197,7 +3208,7 @@
               }],
               # http://gcc.gnu.org/wiki/DebugFission
               # Requires gold and gcc >= 4.8 or clang.
-              ['linux_use_gold_flags==1 and (clang==1 or gcc_version>=48) and binutils_version>=223', {
+              ['linux_use_gold_flags==1 and (clang==1 or gcc_version>=48) and binutils_version>=223 and use_icecc==0', {
                 'cflags': ['-gsplit-dwarf'],
                 'ldflags': ['-Wl,--gdb-index'],
               }],