meson: build .standalone versions of the report binaries

The goal is to be allow the use of those binaries on systemd with older
systemd. The report stuff is generally independent of the running systemd
version.

When built with -Dinstall-tests=true -Dstandalone-binaries=true
-Dbuildtype=release -Db_lto=true, gcc-16.1.1-2.fc44.x86_64, the sizes
are quite reasonable:

$ ls -lG build-lto/*.standalone
-rwxr-xr-x 1 zbyszek  713200 Jul  3 13:16 build-lto/systemd-report.standalone
-rwxr-xr-x 1 zbyszek  662936 Jul  3 13:16 build-lto/systemd-report-basic.standalone
-rwxr-xr-x 1 zbyszek  567424 Jul  3 13:16 build-lto/systemd-report-cgroup.standalone
-rwxr-xr-x 1 zbyszek  592856 Jul  3 13:16 build-lto/systemd-report-files.standalone
-rwxr-xr-x 1 zbyszek  589864 Jul  3 13:16 build-lto/systemd-report-sign-plain.standalone
-rwxr-xr-x 1 zbyszek  548624 Jul  3 13:16 build-lto/systemd-report-sign-tsm.standalone

src/report/meson.build

@@ -1,10 +1,10 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
-executables += [
-        libexec_template + {
+report_executables = [
+        {
                 'name' : 'systemd-report',
                 'public' : true,
-                'sources' : files(
+                'export' : files(
                         'report.c',
                         'report-generate.c',
                         'report-sign.c',
@@ -14,43 +14,63 @@ executables += [
                         libcurl_cflags,
                 ],
         },
-
-        libexec_template + {
+        {
                 'name' : 'systemd-report-basic',
                 'public' : true,
-                'sources' : files(
-                        'report-basic-server.c',
+                'export' : files(
                         'report-basic.c',
+                        'report-basic-server.c',
                 ),
         },
-        libexec_template + {
+        {
                 'name' : 'systemd-report-cgroup',
-                'sources' : files(
+                'export' : files(
                         'report-cgroup.c',
                         'report-cgroup-server.c',
                 ),
         },
-        libexec_template + {
+        {
                 'name' : 'systemd-report-files',
-                'sources' : files(
+                'export' : files(
                         'report-files.c',
                         'report-files-server.c',
                 ),
         },
-        libexec_template + {
+        {
                 'name' : 'systemd-report-sign-plain',
-                'sources' : files(
+                'export' : files(
                         'report-sign-plain.c',
                 ),
                 'dependencies' : libopenssl_cflags,
-                'conditions' : [
-                        'HAVE_OPENSSL',
-                ],
+                'conditions' : ['HAVE_OPENSSL'],
         },
-        libexec_template + {
+        {
                 'name' : 'systemd-report-sign-tsm',
-                'sources' : files(
+                'export' : files(
                         'report-sign-tsm.c',
                 ),
         },
 ]
+
+foreach exe : report_executables
+        exe2 = {
+                'name' : exe['name'] + '.standalone',
+                'import' : [exe['name']],
+                'link_with' : [
+                        libc_wrapper_static,
+                        libbasic_static,
+                        libshared_static,
+                        libsystemd_static,
+                ]
+        }
+        foreach optional : ['public', 'dependencies', 'conditions']
+                if optional in exe
+                        exe2 += { optional : exe[optional] }
+                endif
+        endforeach
+
+        executables += [
+                libexec_template + exe,
+                libexec_template + exe2,
+        ]
+endforeach