This PKGBUILD file installs the Orca program with pacman and makes it available on the system. The main purpose of this PKGBUILD is to track the files installed with pacman and automatically apply some patches. To make use of this PKGBUILD you first have to download the dynamically linked Orca distribution from the Orca forum. Due to Orca's EULA no automatic download will be provided.

To make sure the Orca binaries pick up the liborca_*.so library correctly, an runtime path is set for each binary by using patchelf. This is important since this PKGBUILD installs into /opt/orca/ rather than /usr.

Generally, it is a good idea to patch a dynamically linked Orca installation to ensure the liborca_*.so can always be found:

for f in ./orca* ./autoci*; do
  patchelf --set-rpath '$ORIGIN' "${f}"
done

Since Orca must be called with the full path to use MPI parallelization, a convenience function is installed which defines an orca function to always call the Orca binary with the full path.

orca () {
  /opt/orca/bin/orca "$@"
}

Additionally a module file for lmod is provided. If the lmod package is installed the Orca binaries are not added to the PATH by default. The module file also sets a function to always call the Orca binary with the full path:

local prefix = pathJoin("/opt/orca")

set_shell_function(
  "orca",
  pathJoin(prefix, "bin", "orca") .. " \"$@\"",
  pathJoin(prefix, "bin", "orca") .. " $*")