Make sure all necessary RPM path macros are defined

[Lalufu]

Motivation and Context

When building (s)rpm files through the Makefile, a directory structure is created in /tmp to hold the various files.

In case the user running the command has overridden some of the RPM path settings through their user profile (for example in ~/.rpmmacros), these paths do not line up with the configuration, and the build fails.

Make sure all paths used are properly defined.

How Has This Been Tested?

1. As a user, create a ~/.rpmmacros file with the following content (as an example):

%_topdir                %(echo $HOME)/rpmbuild
%_tmppath               %{_topdir}/TEMP
%_builddir              %{_tmppath}/BUILD

%_rpmtopdir             %{_topdir}/RPM/%{name}
%_sourcedir             %{_rpmtopdir}
%_specdir               %{_rpmtopdir}
%_rpmdir                %{_topdir}/RPMS
%_srcrpmdir             %{_topdir}/RPMS
%_rpmfilename           %%{NAME}-%%{VERSION}-%%{RELEASE}.%%{ARCH}.rpm

2. Without this patch applied, do a ./autogen.sh ; ./configure ; make -j1 srpm run
3. Observe it will fail with errors about failing to find some files
4. Apply the patch
5. Repeat step 2)
6. Observe that the build succeeds

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.