Modify toolchain.gypi to avoid adding -m64 flag on android.

The -m64 flag isn't supported on Android.  Add a similar gyp condition to avoid
setting the flag on Android in a similar manner to how the -m32 flag is avoided
on android.

BUG=354405
LOG=N
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/212863007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20289 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

build/toolchain.gypi

@@ -428,8 +428,12 @@
             'variables': {
               'm64flag': '<!(($(echo ${CXX_target:-<(CXX)}) -m64 -E - > /dev/null 2>&1 < /dev/null) && echo "-m64" || true)',
             },
-            'cflags': [ '<(m64flag)' ],
-            'ldflags': [ '<(m64flag)' ],
+            'conditions': [
+              ['((OS!="android" and OS!="qnx") or clang==1)', {
+                'cflags': [ '<(m64flag)' ],
+                'ldflags': [ '<(m64flag)' ],
+              }],
+            ],
           }]
         ],
       }],