These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.09 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/ossp-uuid-1.6.6::gentoo  USE="cxx -perl -static-libs -verify-sig" PERL_FEATURES="ithreads (-debug) -quadmath" 54 KiB
[ebuild  N     ] dev-libs/libpcre-8.45-r4:3::gentoo  USE="bzip2 cxx jit pcre16 readline (unicode) zlib -libedit -pcre32 -static-libs -valgrind" 1542 KiB
[ebuild  N     ] dev-lang/swi-prolog-10.0.2::gentoo  USE="cli gmp ipc pcre pgo ssl -archive -berkdb -debug -doc -gui -java -minimal -odbc -test -yaml" 12526 KiB

Total: 3 packages (3 new), Size of downloads: 14121 KiB