Description:
Installing packaged kernel module that does not build (for example, currently, openafs-modules-dkms in AUR on 4.5) does not report the build error, nor does pacman exit with a non-zero exit code. The current behavior from pacman is as if module install succeeded. This is not a major issue, but could be more helpful to the user.

The 'dkms -q' command silences not just the build output but also the build error (which is printed without the -q). This is unfortunate, but at least dkms exits with non-zero error code (10) if the build fails. Pacman, however, exists with error code 0, even if dkms exited with a non-zero error code.

Expected behavior: when dkms exits with non-zero code, pacman also exits with non-zero error code. Also, ideally pacman prints a generic error message that 'dkms' invocation failed.

Additional info:
* package version(s): pacman 5.0.1-2

Steps to reproduce:
1. Install openafs-modules-dkms from AUR via yaourt or manually via pacman on Linux kernel 4.5
2. Let dkms attempt to build the modules as part of the installation.
3. Check the error code from pacman: it is 0, but build failed (see log in /var/lib/dkms or manually invoke the same dkms command and 'echo $?' to see '10').