Use gcc by default for gyp untrusted ARM builds

src/untrusted/irt/irt.gyp

Index: src/untrusted/irt/irt.gyp
diff --git a/src/untrusted/irt/irt.gyp b/src/untrusted/irt/irt.gyp
index b34fe69139b74ff2397ea302c5002bd6b509fd75..b20c106131a356bddbb56b182bd9eef1a5352400 100644
--- a/src/untrusted/irt/irt.gyp
+++ b/src/untrusted/irt/irt.gyp
@@ -119,6 +119,11 @@
              '-nostartfiles',
           ],
         }],
+        ['target_arch == "arm"', {
+          'compile_flags': [
+            '-mtp=soft'

[Derek Schuff, 2013/03/28 17:33:41]

seems odd that this is here for arm but the corresponding flags are not here for
x86. does this duplicate something in untrusted.gypi?

[Roland McGrath, 2013/03/28 17:37:54]

See newlib_tls_flags in untrusted.gypi; that uses it for all builds using
newlib, when it's only really needed or desireable for building components of
the IRT.

[Derek Schuff, 2013/03/28 17:49:31]

Got it. so this should only be here, and in whatever nlibs get linked into the
IRT (e.g. gio_lib, platform_lib, srpc_lib etc as listed in the dependencies
above)

[Sam Clegg, 2013/03/28 23:02:59]

Done.  Went for consistency with x86 which is to say that all newlib code built
by gyp has this flag now.

+          ],
+        }],
       ],
       'dependencies': [
         '<(DEPTH)/native_client/tools.gyp:prep_toolchain',