boost @1.50.0 Porfile does not pass configure.c{xx}flags to boost build

[acmorrow (Andrew C. Morrow)]

I've been experimenting with building various macports C++ libraries with XCode 4.5 DP2, with the compiler hardcoded to clang, and with '-std=c++11 -stdlib=libc++' edited into configure.cxxflags in portconfigure.tcl:

default configure.cxxflags {"${configure.optflags} -std=c++11 -stdlib=libc++"}

I'll be the first to admit this is a somewhat exotic setup, but I've actually had surprisingly good success so far.

One problem I have discovered is that my modified configure.cxxflags were not being passed along into the boost build system when building boost. In the Boost Portfile there is a line like this:

write_jam "using darwin : : ${filter}${configure.cxx} ;"

Which configures the user-config.jam file used by boosts build system. Based on the information here:

​http://www.boost.org/boost-build2/doc/html/bbv2/overview/configuration.html

I think that this line should be modified to something more like:

write_jam "using darwin : : ${filter}${configure.cxx} : <compileflags>\"${configure.cppflags}\" <cflags>\"${configure.cflags}\" <cxxflags>\"${configure.cxxflags}\" <linkflags>\"${configure.cxxflags} ${configure.ldflags}\" ;"