PTFM-13637: Omit -std=c++11 for clang boost build
PTFM-13637: Omit -std=c++11 for clang boost build

Summary:
The Mac upload agent is built with -std=c++0x, so we probably shouldn't
force a mismatch when building the boost binaries used by ua.

Test Plan:
Built and tested boost and the Mac upload agent with Apple clang
clang-600.0.56.

Reviewers: psung

Reviewed By: psung

Subscribers: akislyuk

Differential Revision: https://phabricator.dnanexus.com/D207

olegnev/dx-toolkit,andyshinn/dx-toolkit,olegnev/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,andyshinn/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,olegnev/dx-toolkit,dnanexus/dx-toolkit,johnwallace123/dx-toolkit,olegnev/dx-toolkit,olegnev/dx-toolkit,jhuttner/dx-toolkit,jhuttner/dx-toolkit,johnwallace123/dx-toolkit,dnanexus/dx-toolkit,andyshinn/dx-toolkit,johnwallace123/dx-toolkit,andyshinn/dx-toolkit,andyshinn/dx-toolkit,jhuttner/dx-toolkit,dnanexus/dx-toolkit,johnwallace123/dx-toolkit,jhuttner/dx-toolkit,andyshinn/dx-toolkit,olegnev/dx-toolkit,jhuttner/dx-toolkit,andyshinn/dx-toolkit,dnanexus/dx-toolkit,johnwallace123/dx-toolkit,olegnev/dx-toolkit,jhuttner/dx-toolkit,johnwallace123/dx-toolkit,andyshinn/dx-toolkit,johnwallace123/dx-toolkit,olegnev/dx-toolkit,jhuttner/dx-toolkit,johnwallace123/dx-toolkit