Remove USES=compiler:c++11-lib from mail/evolution. While it
fixes the build failure on FreeBSD 8 (and probably 9), the
application fails to start because the base version of libstdc++
is loaded at runtime, which does not satify the requirements
of. The reason is that evolution does not directly link to
libstdc++, so the rpath added to it by USES=compiler:c++11-lib
has no effect. The first shared library that links to
libstdc++ belongs to evolution-data-server, which does not
have USES=compiler:c++11-lib, which causes the base version
of libstdc++ to be loaded.
Unconditionally add USES=compiler:c++11-lib to
databases/evolution-data-server. For standard versions of
FreeBSD 10 and higher on amd64 and i386, it is a no-op,
so there is no harm in enabling it. If FreeBSD 10 or
higher is configured to build with base gcc and clang is
not present, which is an option on amd64 and i386 and is
mandatory on some tier 2 platforms that don't have clang
support, then USES=compiler:c++11-lib is needed.
See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=199746