One of the upstream maintainers (glebm) suggested to use the "src"
tarball instead of "src-fully-vendored", which does not bundle
libraries already available in the repository (SDL2, SDL2_image,
libfmt, bzip2, libsodium, googletest) without the need to specify
dedicated configure flags for them.
gettext is used for generating libdevilutionX.mpq but not required here
because it is shipped in the tarball.
"-DFETCHCONTENT_FULLY_DISCONNECTED=ON" now is globally used in
48dabfa86779c1b32d40055ffc5747ba36332152 after the previous update
for this package, so it is not needed here anymore.
ca1a0d0f98