Use bundled ATM in RHEL builds

If a system libatm is not found, the bundled version will be used as in
previous versions.  The bundled version was imported from 2.4.1 (based
on date) but have not changed since.  This avoids the need to support
the entire linux-atm package in RHEL just for the pppoatm plugin.

ppp.spec

@@ -18,7 +18,7 @@ Name:    ppp
 # These all need to be patched (if necessary) and rebuilt for new
 # versions of ppp.
 Version: 2.5.0
-Release: 2%{?dist}
+Release: 3%{?dist}
 Summary: The Point-to-Point Protocol daemon
 License: BSD and LGPLv2+ and GPLv2+ and Public Domain
 URL:     http://www.samba.org/ppp
@@ -51,7 +51,11 @@ BuildRequires: systemd
 BuildRequires: systemd-devel
 BuildRequires: glib2-devel
 BuildRequires: openssl-devel
+%if %{defined rhel}
+Provides: bundled(linux-atm) = 2.4.1
+%else
 BuildRequires: linux-atm-libs-devel
+%endif
 
 Requires: glibc >= 2.0.6
 Requires: /etc/pam.d/system-auth
@@ -185,6 +189,9 @@ mkdir -p %{buildroot}%{_rundir}/ppp
 %{_libdir}/pkgconfig/pppd.pc
 
 %changelog
+* Tue Jul 25 2023 Yaakov Selkowitz <yselkowi@redhat.com> - 2.5.0-3
+- Use bundled ATM in RHEL builds
+
 * Fri Jul 21 2023 Fedora Release Engineering <releng@fedoraproject.org> - 2.5.0-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild