[build] Switch off warning on gcc bots.

gypfiles/standalone.gypi

Index: gypfiles/standalone.gypi
diff --git a/gypfiles/standalone.gypi b/gypfiles/standalone.gypi
index 7e41ce84aef96d1b2d5f0c8ca23c10a12334893f..5fefe199d6e13b01fdd52ac7a75e522bee2fcb7d 100644
--- a/gypfiles/standalone.gypi
+++ b/gypfiles/standalone.gypi
@@ -503,7 +503,10 @@
     },
     'conditions':[
       ['clang==0', {
-        'cflags+': ['-Wno-sign-compare',],
+        'cflags+': [
+          '-Wno-sign-compare',
+          '-Wno-uninitialized',
+        ],
       }],
       ['clang==1 or host_clang==1', {
         # This is here so that all files get recompiled after a clang roll and