contrib: integrate RPM spec

Remove OpenSUSE bug report link, set version to @VERSION@, make it build
with CentOS 8 etc.

Related: OS#4550
Change-Id: I824b67f2d590ac2aa9f2e4fa4387a5283cf22521

.gitignore

@@ -69,3 +69,5 @@ doc/manuals/generated/
 doc/manuals/osmomsc-usermanual.xml
 doc/manuals/common
 doc/manuals/build
+
+contrib/osmo-sgsn.spec

configure.ac

@@ -273,4 +273,5 @@ AC_OUTPUT(
     doc/manuals/Makefile
     contrib/Makefile
     contrib/systemd/Makefile
+    contrib/osmo-sgsn.spec
     Makefile)

contrib/osmo-sgsn.spec.in

@@ -12,28 +12,26 @@
 # license that conforms to the Open Source Definition (Version 1.9)
 # published by the Open Source Initiative.
 
-# Please submit bugfixes or comments via http://bugs.opensuse.org/
-#
-
-
 ## Disable LTO for now since it breaks compilation of the tests
 ## https://osmocom.org/issues/4116
 %define _lto_cflags %{nil}
 
 %define with_iu 1
 Name:           osmo-sgsn
-Version:        1.6.0.9
+Version:        @VERSION@
 Release:        0
 Summary:        Osmocom's SGSN for 2G and 3G packet-switched mobile networks
 License:        AGPL-3.0-or-later AND GPL-2.0-or-later
 Group:          Productivity/Telephony/Servers
-URL:            https://osmocom.org/projects/osmosgsn/wiki/OsmoSGSN
+URL:            https://osmocom.org/projects/osmosgsn
 Source:         %{name}-%{version}.tar.xz
 BuildRequires:  autoconf
 BuildRequires:  automake
 BuildRequires:  libtool
 BuildRequires:  pkgconfig
+%if 0%{?suse_version}
 BuildRequires:  systemd-rpm-macros
+%endif
 BuildRequires:  pkgconfig(libcares)
 BuildRequires:  pkgconfig(libcrypto) >= 0.9.5
 BuildRequires:  pkgconfig(libgtp) >= 1.4.0
@@ -88,6 +86,7 @@ make %{?_smp_mflags}
 %install
 %make_install
 
+%if 0%{?suse_version}
 %preun  %service_del_preun  %{name}.service
 %postun %service_del_postun %{name}.service
 %pre    %service_add_pre    %{name}.service
@@ -100,6 +99,7 @@ make %{?_smp_mflags}
 %postun -n osmo-gbproxy %service_del_postun osmo-gbproxy.service
 %pre    -n osmo-gbproxy %service_add_pre    osmo-gbproxy.service
 %post   -n osmo-gbproxy %service_add_post   osmo-gbproxy.service
+%endif
 
 %check
 make %{?_smp_mflags} check || (find . -name testsuite.log -exec cat {} +)