journal: properly mark two definitions that are deprecated with GCC attributes for that

src/journal-remote/journal-upload.c

@@ -754,9 +754,13 @@ static int open_journal(sd_journal **j) {
                 r = sd_journal_open_directory(j, arg_directory, arg_journal_type);
         else if (arg_file)
                 r = sd_journal_open_files(j, (const char**) arg_file, 0);
-        else if (arg_machine)
+        else if (arg_machine) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+                /* FIXME: replace with D-Bus call OpenMachineRootDirectory() so that things also work with raw disk images */
                 r = sd_journal_open_container(j, arg_machine, 0);
-        else
+#pragma GCC diagnostic pop
+        } else
                 r = sd_journal_open(j, !arg_merge*SD_JOURNAL_LOCAL_ONLY + arg_journal_type);
         if (r < 0)
                 log_error_errno(r, "Failed to open %s: %m",

src/journal/sd-journal.c

@@ -1875,7 +1875,7 @@ _public_ int sd_journal_open_container(sd_journal **ret, const char *machine, in
         char *p;
         int r;
 
-        /* This is pretty much deprecated, people should use machined's OpenMachineRootDirectory() call instead in
+        /* This is deprecated, people should use machined's OpenMachineRootDirectory() call instead in
          * combination with sd_journal_open_directory_fd(). */
 
         assert_return(machine, -EINVAL);

src/systemd/_sd-common.h

@@ -45,6 +45,18 @@ typedef void (*_sd_destroy_t)(void *userdata);
 #  define _sd_pure_ __attribute__((__pure__))
 #endif
 
+/* Note that strictly speaking __deprecated__ has been available before GCC 6. However, starting with GCC 6
+ * it also works on enum values, which we are interested in. Since this is a developer-facing feature anyway
+ * (as opposed to build engineer-facing), let's hence conditionalize this to gcc 6, given that the developers
+ * are probably going to use something newer anyway. */
+#ifndef _sd_deprecated_
+#  if __GNUC__ >= 6
+#    define _sd_deprecated_ __attribute__((__deprecated__))
+#  else
+#    define _sd_deprecated_
+#  endif
+#endif
+
 #ifndef _SD_STRINGIFY
 #  define _SD_XSTRINGIFY(x) #x
 #  define _SD_STRINGIFY(x) _SD_XSTRINGIFY(x)

src/systemd/sd-journal.h

@@ -70,7 +70,7 @@ enum {
         SD_JOURNAL_CURRENT_USER = 1 << 3,
         SD_JOURNAL_OS_ROOT      = 1 << 4,
 
-        SD_JOURNAL_SYSTEM_ONLY = SD_JOURNAL_SYSTEM /* deprecated name */
+        SD_JOURNAL_SYSTEM_ONLY _sd_deprecated_ = SD_JOURNAL_SYSTEM /* deprecated name */
 };
 
 /* Wakeup event types */
@@ -85,7 +85,7 @@ int sd_journal_open_directory(sd_journal **ret, const char *path, int flags);
 int sd_journal_open_directory_fd(sd_journal **ret, int fd, int flags);
 int sd_journal_open_files(sd_journal **ret, const char **paths, int flags);
 int sd_journal_open_files_fd(sd_journal **ret, int fds[], unsigned n_fds, int flags);
-int sd_journal_open_container(sd_journal **ret, const char *machine, int flags); /* deprecated */
+int sd_journal_open_container(sd_journal **ret, const char *machine, int flags) _sd_deprecated_; /* deprecated */
 void sd_journal_close(sd_journal *j);
 
 int sd_journal_previous(sd_journal *j);

src/test/generate-sym-test.py

@@ -6,6 +6,9 @@ for header in sys.argv[2:]:
     print('#include "{}"'.format(header.split('/')[-1]))
 
 print('''
+/* We want to check deprecated symbols too, without complaining */
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 const void* symbols[] = {''')
 
 for line in open(sys.argv[1]):