libgap installs headers to $includedir/gap

[sagetrac-felixs]

gap headers and libgap headers can coexist if both are installed to their respective $pkgincludedir. libgap headers should go into $prefix/include/libgap.

The references to the headers need to be changed accordingly.

Depends on #14804

Upstream: Not yet reported upstream; Will do shortly.

CC: @jondo

Component: packages: standard

Author: Felix Salfelder

Branch/Commit: u/felixs/libgap_include @ 8bb4a27

Issue created by migration from https://trac.sagemath.org/ticket/15112

[sagetrac-git]

Changed commit from 54c85ca to 8bb4a27

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

[changeset:8bb4a27]

apply patches from patchdir

[sagetrac-felixs]

Dependencies: #14804

[sagetrac-felixs]

comment:3

Now using unified patcher (#14804).

[jdemeyer]

comment:6

Obsolete by the upgrade to GAP-4.10 (#22626).