build-sys: only install libexecdir/resolv.conf if resolved is enabled (#5826)

as mentioned in https://github.com/systemd/systemd/pull/5811

Makefile.am

@@ -5599,6 +5599,9 @@ GENERAL_ALIASES += \
 nodist_pkgsysconf_DATA += \
 	src/resolve/resolved.conf
 
+dist_rootlibexec_DATA += \
+	src/resolve/resolv.conf
+
 libnss_resolve_la_SOURCES = \
 	src/nss-resolve/nss-resolve.sym \
 	src/nss-resolve/nss-resolve.c
@@ -5737,9 +5740,6 @@ EXTRA_DIST += \
 	units/systemd-resolved.service.m4.in \
 	src/resolve/resolved.conf.in
 
-dist_rootlibexec_DATA += \
-	src/resolve/resolv.conf
-
 # ------------------------------------------------------------------------------
 if ENABLE_NETWORKD
 rootlibexec_PROGRAMS += \

src/resolve/meson.build

@@ -135,10 +135,10 @@ if conf.get('ENABLE_RESOLVED', 0) == 1
                 configuration : substs)
         install_data(resolved_conf,
                      install_dir : pkgsysconfdir)
-endif
 
-install_data('resolv.conf',
-             install_dir : rootlibexecdir)
+        install_data('resolv.conf',
+                     install_dir : rootlibexecdir)
+endif
 
 tests += [
         [['src/resolve/test-resolve-tables.c',