packaging/fedora: Add Amazon Linux 2 support

Amazon Linux 2 is a derivative of Red Hat Enterprise Linux 7, using
a combination of CentOS 7 sources, backports from Fedora, and custom
packages produced by the Amazon Linux team to provide an updated stack
on a stable base platform.

As the Fedora packaging is already most of the way there for supporting
RHEL/CentOS 7, we can easily enable Amazon Linux 2, as well.

Note that the packaging assumes that EPEL for EL7 is activated on Amazon
Linux 2, as we require packages from EPEL for installation.

Signed-off-by: Neal Gompa <[email protected]>

packaging/amzn-2

@@ -0,0 +1 @@
+fedora

packaging/fedora/snapd.spec

@@ -9,6 +9,14 @@
 # Compat macros
 %{?!_environmentdir: %global _environmentdir %{_prefix}/lib/environment.d}
 
+# With Amazon Linux 2+, we're going to provide the /snap symlink by default,
+# since classic snaps currently require it... :(
+%if 0%{?amzn} >= 2
+%bcond_without snap_symlink
+%else
+%bcond_with snap_symlink
+%endif
+
 # A switch to allow building the package with support for testkeys which
 # are used for the spread test suite of snapd.
 %bcond_with testkeys
@@ -554,6 +562,11 @@ echo 'SNAP_REEXEC=0' > %{buildroot}%{_sysconfdir}/sysconfig/snapd
 touch %{buildroot}%{_sharedstatedir}/snapd/state.json
 touch %{buildroot}%{_sharedstatedir}/snapd/snap/README
 
+# When enabled, create a symlink for /snap to point to /var/lib/snapd/snap
+%if %{with snap_symlink}
+ln -sr %{buildroot}%{_sharestatedir}/snapd/snap %{buildroot}/snap
+%endif
+
 # source codes for building projects
 %if 0%{?with_devel}
 install -d -p %{buildroot}/%{gopath}/src/%{import_path}/
@@ -653,6 +666,9 @@ popd
 %ghost %{_sharedstatedir}/snapd/state.json
 %ghost %{_sharedstatedir}/snapd/snap/README
 %{_environmentdir}/990-snapd.conf
+%if %{with snap_symlink}
+/snap
+%endif
 
 %files -n snap-confine
 %doc cmd/snap-confine/PORTING