Emerging media-gfx/exiv2-0.21 fails with: xmp.cpp:423: error: prototype for ‘bool Exiv2::XmpParser::registerNs(const std::string&, const std::string&)’ does not match any in class ‘Exiv2::XmpParser’ xmp.hpp:327: error: candidate is: static void Exiv2::XmpParser::registerNs(const std::string&, const std::string&) make[1]: *** [xmp.o] Error 1 make[1]: *** Waiting for unfinished jobs.... Reproducible: Always
This bug seems to be related to the use of the +xmp use flag. With xmp enabled, everything compiles as expected. I manually tried to build the source with ./configure --disable-xmp, and it failed as well. So you could get around this by just enabling the xmp use flag in package.use but of course, that's just a dirty workaround. I suppose this is an upstream problem, although i couldn't find a bug report in exiv2.org's issue tracker.
*** This bug has been marked as a duplicate of bug 349091 ***