tree-wide: make constant ratelimit compound actually const

The compiler should recognize that these are constant expressions, but
let's better make this explicit, so that the linker can safely share the
initializations all over the place.

src/basic/fs-util.c

@@ -903,7 +903,7 @@ int posix_fallocate_loop(int fd, uint64_t offset, uint64_t size) {
 
         /* On EINTR try a couple of times more, but protect against busy looping
          * (not more than 16 times per 10s) */
-        rl = (RateLimit) { 10 * USEC_PER_SEC, 16 };
+        rl = (const RateLimit) { 10 * USEC_PER_SEC, 16 };
         while (ratelimit_below(&rl)) {
                 r = posix_fallocate(fd, offset, size);
                 if (r != EINTR)

src/core/manager.c

@@ -890,7 +890,7 @@ int manager_new(LookupScope scope, ManagerTestRunFlags test_run_flags, Manager *
         }
 
         /* Reboot immediately if the user hits C-A-D more often than 7x per 2s */
-        m->ctrl_alt_del_ratelimit = (RateLimit) { .interval = 2 * USEC_PER_SEC, .burst = 7 };
+        m->ctrl_alt_del_ratelimit = (const RateLimit) { .interval = 2 * USEC_PER_SEC, .burst = 7 };
 
         r = manager_default_environment(m);
         if (r < 0)

src/core/unit.c

@@ -127,7 +127,7 @@ Unit* unit_new(Manager *m, size_t size) {
         u->last_section_private = -1;
 
         u->start_ratelimit = (RateLimit) { m->default_start_limit_interval, m->default_start_limit_burst };
-        u->auto_start_stop_ratelimit = (RateLimit) { 10 * USEC_PER_SEC, 16 };
+        u->auto_start_stop_ratelimit = (const RateLimit) { 10 * USEC_PER_SEC, 16 };
 
         return u;
 }

src/import/import-fs.c

@@ -188,7 +188,7 @@ static int import_fs(int argc, char *argv[], void *userdata) {
 
         (void) mkdir_parents_label(dest, 0700);
 
-        progress.limit = (RateLimit) { 200*USEC_PER_MSEC, 1 };
+        progress.limit = (const RateLimit) { 200*USEC_PER_MSEC, 1 };
 
         {
                 BLOCK_SIGNALS(SIGINT, SIGTERM);

src/journal/journald-server.c

@@ -83,7 +83,7 @@
 
 #define IDLE_TIMEOUT_USEC (30*USEC_PER_SEC)
 
-#define FAILED_TO_WRITE_ENTRY_RATELIMIT ((RateLimit) { .interval = 1 * USEC_PER_SEC, .burst = 1 })
+#define FAILED_TO_WRITE_ENTRY_RATELIMIT ((const RateLimit) { .interval = 1 * USEC_PER_SEC, .burst = 1 })
 
 static int determine_path_usage(
                 Server *s,

src/journal/journald-server.h

@@ -20,7 +20,7 @@ typedef struct Server Server;
 #include "time-util.h"
 #include "varlink.h"
 
-#define JOURNALD_LOG_RATELIMIT ((RateLimit) { .interval = 60 * USEC_PER_SEC, .burst = 3 })
+#define JOURNALD_LOG_RATELIMIT ((const RateLimit) { .interval = 60 * USEC_PER_SEC, .burst = 3 })
 
 typedef enum Storage {
         STORAGE_AUTO,

src/libsystemd/sd-journal/journal-file.c

@@ -4163,7 +4163,7 @@ int journal_file_get_cutoff_monotonic_usec(JournalFile *f, sd_id128_t boot_id, u
 
 /* Ideally this would be a function parameter but initializers for static fields have to be compile
  * time constants so we hardcode the interval instead. */
-#define LOG_RATELIMIT ((RateLimit) { .interval = 60 * USEC_PER_SEC, .burst = 3 })
+#define LOG_RATELIMIT ((const RateLimit) { .interval = 60 * USEC_PER_SEC, .burst = 3 })
 
 bool journal_file_rotate_suggested(JournalFile *f, usec_t max_file_usec, int log_level) {
         assert(f);

src/resolve/resolved-dns-scope.c

@@ -71,7 +71,7 @@ int dns_scope_new(Manager *m, DnsScope **ret, Link *l, DnsProtocol protocol, int
         log_debug("New scope on link %s, protocol %s, family %s", l ? l->ifname : "*", dns_protocol_to_string(protocol), family == AF_UNSPEC ? "*" : af_to_name(family));
 
         /* Enforce ratelimiting for the multicast protocols */
-        s->ratelimit = (RateLimit) { MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST };
+        s->ratelimit = (const RateLimit) { MULTICAST_RATELIMIT_INTERVAL_USEC, MULTICAST_RATELIMIT_BURST };
 
         *ret = s;
         return 0;

src/test/test-ratelimit.c

@@ -18,7 +18,7 @@ TEST(ratelimit_below) {
         for (i = 0; i < 10; i++)
                 assert_se(ratelimit_below(&ratelimit));
 
-        ratelimit = (RateLimit) { 0, 10 };
+        ratelimit = (const RateLimit) { 0, 10 };
         for (i = 0; i < 10000; i++)
                 assert_se(ratelimit_below(&ratelimit));
 }

src/timesync/timesyncd-manager.c

@@ -1112,7 +1112,7 @@ int manager_new(Manager **ret) {
 
                 .server_socket = -1,
 
-                .ratelimit = (RateLimit) {
+                .ratelimit = (const RateLimit) {
                         RATELIMIT_INTERVAL_USEC,
                         RATELIMIT_BURST
                 },