RPM: Add missing BuildRequires for PAM component

When the optional PAM binaries are included in a build, ./configure will
look for security/pam_modules.h and - if it doesn't find it - recommend
the user install `libpam0g-dev`.  On Red Hat systems, `pam-devel` is the
package that supplies this requirement; `libpam0g-dev` does not exist.

By encoding this requirement in the spec file, we give packagers more
appropriate (and timely) recommendations for completing the build.

Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Chris Lindee <[email protected]>
Closes openzfs#13001

rpm/generic/zfs.spec.in

@@ -148,10 +148,15 @@ BuildRequires:  ncompress
 BuildRequires:  libtirpc-devel
 %endif
 
+%if %{with pam}
+BuildRequires:  pam-devel
+%endif
+
 Requires:       openssl
 %if 0%{?_systemd}
 BuildRequires: systemd
 %endif
+
 %endif
 
 %if 0%{?_systemd}