Hi all, I am trying to compile boost on Mac OS X 10.9.5 for 32 and 64 bit. I am using the following command: ./b2 link=static threading=multi architecture=x86 address-model=32_64 I get the following error message: darwin.compile.c++.pch bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch clang: error: cannot use 'precompiled-header' output with multiple -arch options "g++" -x c++-header -O3 -finline-functions -Wno-inline -Wall -gdwarf-2 -fexceptions -arch i386 -arch x86_64 -DBOOST_ALL_NO_LIB=1 -DBOOST_BUILD_PCH_ENABLED -DNDEBUG -I"." -I"libs/math/src/tr1" -c -o "bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch" "libs/math/build/../src/tr1/pch.hpp" ...failed darwin.compile.c++.pch bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch... Then 144 targets are skipped. Does anyone knows how to fix this? Thanks in advance Kevin