nspawn: fix comparisons of versions with non-numerical suffixes

See a2b0cd3f5ab3f450e74e2085ad20372a05451c74. When -Dshared-lib-tag is used,
libsystemd-shared.so and libsystemd-core.so get a suffix which breaks the
parsing done by systemd_installation_has_version(). We can assume that the
tag will be something like "251-rc1-1.fc37" that is currently used in Fedora.
(Anything that does *not* start with the version would be completely crazy.)
By switching to strverscmp_improved() we simplify the code and fix comparisons
with such versions.

$ build/test-nspawn-util /var/lib/machines/rawhide
...
Found libsystemd shared at "/var/lib/machines/rawhide/lib/systemd/libsystemd-shared-251-rc1-1.fc37.so.so", version 251-rc1-1.fc37 (OK).
/var/lib/machines/rawhide has systemd >= 251: yes
...

I noticed this when I started a systemd-nspawn container with Redora rawhide
and got the message "Not running with unified cgroup hierarchy, LSM BPF is not
supported". I thought the message is in error, but it was actually correct:
nspawn was misdetecting that the container does not sport new-enough systemd
to support cgroups-v2.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/nspawn/test-nspawn-util.c b/src/nspawn/test-nspawn-util.c
index 7d55db8934..ed68063630 100644
--- a/src/nspawn/test-nspawn-util.c
+++ b/src/nspawn/test-nspawn-util.c
@@ -2,17 +2,17 @@
 
 #include "nspawn-util.h"
 #include "string-util.h"
+#include "strv.h"
 #include "tests.h"
 
 TEST(systemd_installation_has_version) {
-        static const unsigned versions[] = {0, 231, PROJECT_VERSION, 999};
         int r;
 
-        for (size_t i = 0; i < ELEMENTSOF(versions); i++) {
-                r = systemd_installation_has_version(saved_argv[1], versions[i]);
+        FOREACH_STRING(version, "0", "231", STRINGIFY(PROJECT_VERSION), "999") {
+                r = systemd_installation_has_version(saved_argv[1], version);
                 assert_se(r >= 0);
-                log_info("%s has systemd >= %u: %s",
-                         saved_argv[1] ?: "Current installation", versions[i], yes_no(r));
+                log_info("%s has systemd >= %s: %s",
+                         saved_argv[1] ?: "Current installation", version, yes_no(r));
         }
 }