Remove static linking of libgcc and libstdc++ on Mac (since this breaks exception handling and threading).
Remove static linking of libgcc and libstdc++ on Mac (since this
breaks exception handling and threading).

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