[MacPorts] #57513: bazel @0.18.0: error: no type named 'unique_ptr' in namespace 'std'

[MacPorts]

#57513: bazel @0.18.0: error: no type named 'unique_ptr' in namespace 'std'
-------------------------+--------------------------
  Reporter:  ryandesign  |      Owner:  RootFunction
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  bazel       |
-------------------------+--------------------------

Comment (by cjones051073):

 It already uses the cxx11 portgroup. Please check the portfile. Getting
 bazel to use Macports own compiler was enough of a headache ;)

 The issue is the use of the flag -std=c++0x

 ```
 external/local_config_cc/cc_wrapper.sh -U_FORTIFY_SOURCE -fstack-protector
 -Wall -Wthread-safety -Wself-assign -fcolor-diagnostics -fno-omit-frame-
 pointer -g0 -O2 '-D_FORTIFY_SOURCE=1' -DNDEBUG -ffunction-sections -fdata-
 sections '-std=c++0x' -MD -MF bazel-out/darwin-
 opt/bin/src/main/cpp/util/_objs/strings/strings.d '-frandom-seed=bazel-out
 /darwin-opt/bin/src/main/cpp/util/_objs/strings/strings.o'
 -DBLAZE_OPENSOURCE -iquote . -iquote bazel-out/darwin-opt/genfiles -iquote
 bazel-out/darwin-opt/bin -iquote external/bazel_tools -iquote bazel-out
 /darwin-opt/genfiles/external/bazel_tools -iquote bazel-out/darwin-
 opt/bin/external/bazel_tools -no-canonical-prefixes -Wno-builtin-macro-
 redefined '-D__DATE__="redacted"' '-D__TIMESTAMP__="redacted"'
 '-D__TIME__="redacted"' -c src/main/cpp/util/strings.cc -o bazel-out
 /darwin-opt/bin/src/main/cpp/util/_objs/strings/strings.o)

 that needs to be at least `c++11` for `unique_ptr`.

 I have no idea why this only happens on  10.8, whereas 10.9 which is also
 using Macports clang 5.0 seems OK.
 ```

-- 
Ticket URL: <https://trac.macports.org/ticket/57513#comment:1>
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