There are two namespaces that bitbake concerns itself with - recipe names (a.k.a. build time targets) and package names (a.k.a. runtime targets). You can specify a build time target on the bitbake command line, but not a runtime target; you need to find the recipe that provides the package you are trying to build and build that instead (or simply add that package to your image and build the image). In current versions bitbake will at least tell you which recipes have matching or similar-sounding runtime provides (RPROVIDES) so that you'll usually get a hint on which recipe you need to build.