* Avoid duplication of SDB headers in libr/include
SDB is an external project and as such it should live in shlr. However,
for simplicity in dealing with the include flags, the SDB headers were
copied in libr/include as well. This patch just keeps the SDB files
confined in shlr/sdb and make sure various r_* libs use the headers from
there.
* Fix pkgconfig file generation
