sysv-generator: make sysv deprecation message a bit "louder"

Let's add a catalog entry, make the log record structured, and most
importantly, let's add warning emojis.

Just to underline that this stuff should really go away.

src/systemd/sd-messages.h

@@ -198,6 +198,9 @@ _SD_BEGIN_DECLARATIONS;
 #define SD_MESSAGE_MEMORY_TRIM                        SD_ID128_MAKE(f9,b0,be,46,5a,d5,40,d0,85,0a,d3,21,72,d5,7c,21)
 #define SD_MESSAGE_MEMORY_TRIM_STR                    SD_ID128_MAKE_STR(f9,b0,be,46,5a,d5,40,d0,85,0a,d3,21,72,d5,7c,21)
 
+#define SD_MESSAGE_SYSV_GENERATOR_DEPRECATED          SD_ID128_MAKE(a8,fa,8d,ac,db,1d,44,3e,95,03,b8,be,36,7a,6a,db)
+#define SD_MESSAGE_SYSV_GENERATOR_DEPRECATED_STR      SD_ID128_MAKE_STR(a8,fa,8d,ac,db,1d,44,3e,95,03,b8,be,36,7a,6a,db)
+
 _SD_END_DECLARATIONS;
 
 #endif

src/sysv-generator/sysv-generator.c

@@ -4,6 +4,8 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include "sd-messages.h"
+
 #include "alloc-util.h"
 #include "dirent-util.h"
 #include "exit-status.h"
@@ -758,9 +760,16 @@ static int enumerate_sysv(const LookupPaths *lp, Hashmap *all_services) {
                         if (!fpath)
                                 return log_oom();
 
-                        log_warning("SysV service '%s' lacks a native systemd unit file. "
-                                    "Automatically generating a unit file for compatibility. "
-                                    "Please update package to include a native systemd unit file, in order to make it more safe and robust.", fpath);
+                        log_struct(LOG_WARNING,
+                                   LOG_MESSAGE("SysV service '%s' lacks a native systemd unit file. "
+                                               "%s Automatically generating a unit file for compatibility. Please update package to include a native systemd unit file, in order to make it safe, robust and future-proof. "
+                                               "%s This compatibility logic is deprecated, expect removal soon. %s",
+                                               fpath,
+                                               special_glyph(SPECIAL_GLYPH_RECYCLING),
+                                               special_glyph(SPECIAL_GLYPH_WARNING_SIGN), special_glyph(SPECIAL_GLYPH_WARNING_SIGN)),
+                                   "MESSAGE_ID=" SD_MESSAGE_SYSV_GENERATOR_DEPRECATED_STR,
+                                   "SYSVSCRIPT=%s", fpath,
+                                   "UNIT=%s", name);
 
                         service = new(SysvStub, 1);
                         if (!service)