add pkgconfig file to cmake build system

[loriab]

A packager wanted this (psi4/psi4#1589) so that a CMake-built libint can be detected by both cmake and libtool downstream buildsystems. The CMake LibintConfig.cmake and friends are too involved to be imitated by libtool.

I constructed the .pc file by analogy to Libxc https://gitlab.com/libxc/libxc/blob/master/cmake/libxc.pc.in and https://gitlab.com/libxc/libxc/blob/master/build/libxc.pc.in . It builds and looks like the below, but I haven't tried out its consumption in a downstream libtool build.

>>> cat install-am4/lib64/pkgconfig/libint.pc 
prefix=/home/psilocaluser/gits/libint/install-am4
exec_prefix=/home/psilocaluser/gits/libint/install-am4
libdir=/home/psilocaluser/gits/libint/install-am4/lib64
includedir=/home/psilocaluser/gits/libint/install-am4/include

Name: libint
Description: a library for the evaluation of molecular integrals of many-body operators over Gaussian functions
Version: 1.2.1
Libs: -L${libdir} -lderiv -lint
Cflags: -I${includedir} -I${includedir}/libint -I${includedir}/libderiv

[evaleev]

looks good. do I need to bump the version?

[loriab]

Thanks for the merge. There's Ninja, Windows, and pkgconfig changes since v1.2.1, so a version bump is justifiable but not necessary on Psi's account -- your call.

[evaleev]

Ok just wanted to make sure that you guys don't rely on semantic versioning for tracking libint dependency.

…

On Sat, Apr 6, 2019, 9:31 AM Lori A. Burns ***@***.***> wrote: Thanks for the merge. There's Ninja, Windows, and pkgconfig changes since v1.2.1, so a version bump is justifiable but not necessary on Psi's account -- your call. — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#120 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACF0Z86cyEb7OadyT2L3bbF-PU2v7xSMks5veKGxgaJpZM4cf6PG> .