ci: add build/unit-test coverage for armv7 (#42386)

arm64 hosts support running armv7 (armhf) binaries, so we can
cross compile and run the unit tests without performance issues.

armv7 (armhf) is a primary architecture on Ubuntu, so build
regressions block new version updates, and adding coverage
helps to avoid introducing regressions.

src/core/unit.c

@@ -2338,7 +2338,7 @@ static void retroactively_stop_dependencies(Unit *u) {
 
 void unit_start_on_termination_deps(Unit *u, UnitDependencyAtom atom) {
         const char *dependency_name = NULL;
-        JobMode job_mode;
+        JobMode job_mode = _JOB_MODE_INVALID;
         unsigned n_jobs = 0;
         int r;
 

src/sysupdate/sysupdate-transfer.c

@@ -1343,7 +1343,7 @@ int transfer_acquire_instance(Transfer *t, Instance *i, InstanceMetadata *f, Tra
                  * download. */
 
                 if (!i->metadata.sha256sum_set)
-                        return log_error_errno(r, "SHA256 checksum not known for download '%s', refusing.", i->path);
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "SHA256 checksum not known for download '%s', refusing.", i->path);
 
                 digest = hexmem(i->metadata.sha256sum, sizeof(i->metadata.sha256sum));
                 if (!digest)

src/test/meson.build

@@ -547,6 +547,7 @@ executables += [
         core_test_template + {
                 'sources' : files('test-execute.c'),
                 'dependencies' : common_test_dependencies,
+                'type' : meson.is_cross_build() ? 'manual' : '',
                 'timeout' : 360,
         },
         core_test_template + {

src/test/test-crypto-util.c

@@ -129,7 +129,7 @@ static const struct {
 };
 
 TEST(digest_size) {
-        size_t size;
+        size_t size = 0;  /* avoid false maybe-uninitialized warning */
 
         FOREACH_ELEMENT(t, digest_size_table) {
                 assert(openssl_digest_size(t->alg, &size) >= 0);

src/ukify/test/meson.build

@@ -12,10 +12,15 @@ if want_ukify and want_tests != 'false'
                 args += ['--flakes']
         endif
 
+        efi_addon_for_test = ''
+        if not meson.is_cross_build() and efi_addon.length() > 0
+                efi_addon_for_test = efi_addon[0].full_path()
+        endif
+
         test('test-ukify',
              files('test_ukify.py'),
              args: args,
-             env : test_env + {'EFI_ADDON' : efi_addon.length() > 0 ? efi_addon[0].full_path() : ''},
+             env : test_env + {'EFI_ADDON' : efi_addon_for_test},
              timeout : 120,
              suite : 'ukify',
              depends : efi_addon)