Certain rpc headers are needed for compiling getaddrinfo.c. Unfortunatly
that means we have to generate _a few_ header files which we do when we
prepare the libc.
These header files need to be created before the symlinks. Also, some of
these header files depend on a patch. Therefore we apply the patches
first, generate the header files and in the end we create the symlinks.
Fixes#296.
8c306bde67