dev-libs/libpcre can be compiled without C++ support (you lose the C++ wrapper but the core functionality is of course still there). There's a --disable-cpp flag that can be passed to configure to compile it without C++ support. I added a `nocxx' use flag which enables this mode (patch to follow).
Created attachment 125135 [details, diff] Add nocxx use flag to dev-libs/libpcre-7.2.ebuild
Created attachment 125196 [details, diff] Add nocxx use flag to dev-libs/libpcre-7.2.ebuild fix for 7.2's configure script, which also needs an epunt_cxx
Fixed in 7.4-r1.