fixes build on linunx/clang/libc++ combo
fixes build on linunx/clang/libc++ combo

detect on C++ std library implementation

chitianhao/trafficserver,vmamidi/trafficserver,davidbz/trafficserver,davidbz/trafficserver,persiaAziz/trafficserver,dyrock/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,davidbz/trafficserver,davidbz/trafficserver,dyrock/trafficserver,bryancall/trafficserver,pbchou/trafficserver,pbchou/trafficserver,chitianhao/trafficserver,duke8253/trafficserver,duke8253/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,bryancall/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,dyrock/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,pbchou/trafficserver,persiaAziz/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,pbchou/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,duke8253/trafficserver,bryancall/trafficserver,pbchou/trafficserver,bryancall/trafficserver,duke8253/trafficserver,davidbz/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,bryancall/trafficserver,duke8253/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver