Use SIGNAL_ARGS consistently to declare signal handlers.

Various bits of code were declaring signal handlers manually,
using "int signum" or variants of that.  We evidently have no
platforms where that's actually wrong, but let's use our
SIGNAL_ARGS macro everywhere anyway.  If nothing else, it's
good for finding signal handlers easily.

No need for back-patch, since this is just cosmetic AFAICS.

Discussion: https://postgr.es/m/2684964.1663167995@sss.pgh.pa.us

src/backend/storage/ipc/pmsignal.c

@@ -88,7 +88,7 @@ NON_EXEC_STATIC volatile PMSignalData *PMSignalState = NULL;
 volatile sig_atomic_t postmaster_possibly_dead = false;
 
 static void
-postmaster_death_handler(int signo)
+postmaster_death_handler(SIGNAL_ARGS)
 {
 	postmaster_possibly_dead = true;
 }

src/bin/initdb/initdb.c

@@ -268,7 +268,7 @@ static void load_plpgsql(FILE *cmdfd);
 static void vacuum_db(FILE *cmdfd);
 static void make_template0(FILE *cmdfd);
 static void make_postgres(FILE *cmdfd);
-static void trapsig(int signum);
+static void trapsig(SIGNAL_ARGS);
 static void check_ok(void);
 static char *escape_quotes(const char *src);
 static char *escape_quotes_bki(const char *src);
@@ -1848,10 +1848,10 @@ make_postgres(FILE *cmdfd)
  * So this will need some testing on Windows.
  */
 static void
-trapsig(int signum)
+trapsig(SIGNAL_ARGS)
 {
 	/* handle systems that reset the handler, like Windows (grr) */
-	pqsignal(signum, trapsig);
+	pqsignal(postgres_signal_arg, trapsig);
 	caught_signal = true;
 }
 

src/bin/pg_basebackup/pg_receivewal.c

@@ -679,7 +679,7 @@ StreamLog(void)
 #ifndef WIN32
 
 static void
-sigexit_handler(int signum)
+sigexit_handler(SIGNAL_ARGS)
 {
 	time_to_stop = true;
 }

src/bin/pg_basebackup/pg_recvlogical.c

@@ -654,7 +654,7 @@ error:
  * possible moment.
  */
 static void
-sigexit_handler(int signum)
+sigexit_handler(SIGNAL_ARGS)
 {
 	time_to_abort = true;
 }
@@ -663,7 +663,7 @@ sigexit_handler(int signum)
  * Trigger the output file to be reopened.
  */
 static void
-sighup_handler(int signum)
+sighup_handler(SIGNAL_ARGS)
 {
 	output_reopen = true;
 }

src/bin/pg_ctl/pg_ctl.c

@@ -850,7 +850,7 @@ read_post_opts(void)
  * waiting for the server to start up, the server launch is aborted.
  */
 static void
-trap_sigint_during_startup(int sig)
+trap_sigint_during_startup(SIGNAL_ARGS)
 {
 	if (postmasterPID != -1)
 	{
@@ -863,8 +863,8 @@ trap_sigint_during_startup(int sig)
 	 * Clear the signal handler, and send the signal again, to terminate the
 	 * process as normal.
 	 */
-	pqsignal(SIGINT, SIG_DFL);
+	pqsignal(postgres_signal_arg, SIG_DFL);
-	raise(SIGINT);
+	raise(postgres_signal_arg);
 }
 
 static char *

src/bin/pg_test_fsync/pg_test_fsync.c

@@ -81,11 +81,11 @@ static void test_open_sync(const char *msg, int writes_size);
 static void test_file_descriptor_sync(void);
 
 #ifndef WIN32
-static void process_alarm(int sig);
+static void process_alarm(SIGNAL_ARGS);
 #else
 static DWORD WINAPI process_alarm(LPVOID param);
 #endif
-static void signal_cleanup(int sig);
+static void signal_cleanup(SIGNAL_ARGS);
 
 #ifdef HAVE_FSYNC_WRITETHROUGH
 static int	pg_fsync_writethrough(int fd);
@@ -590,14 +590,14 @@ test_non_sync(void)
 }
 
 static void
-signal_cleanup(int signum)
+signal_cleanup(SIGNAL_ARGS)
 {
 	/* Delete the file if it exists. Ignore errors */
 	if (needs_unlink)
 		unlink(filename);
 	/* Finish incomplete line on stdout */
 	puts("");
-	exit(signum);
+	exit(1);
 }
 
 #ifdef HAVE_FSYNC_WRITETHROUGH
@@ -632,7 +632,7 @@ print_elapse(struct timeval start_t, struct timeval stop_t, int ops)
 
 #ifndef WIN32
 static void
-process_alarm(int sig)
+process_alarm(SIGNAL_ARGS)
 {
 	alarm_triggered = true;
 }

src/bin/pg_waldump/pg_waldump.c

@@ -80,7 +80,7 @@ typedef struct XLogDumpConfig
 #ifndef WIN32
 
 static void
-sigint_handler(int signum)
+sigint_handler(SIGNAL_ARGS)
 {
 	time_to_stop = true;
 }

src/include/port.h

@@ -472,7 +472,7 @@ extern int	pg_check_dir(const char *dir);
 extern int	pg_mkdir_p(char *path, int omode);
 
 /* port/pqsignal.c */
-typedef void (*pqsigfunc) (int signo);
+typedef void (*pqsigfunc) (SIGNAL_ARGS);
 extern pqsigfunc pqsignal(int signo, pqsigfunc func);
 
 /* port/quotes.c */

src/test/regress/pg_regress.c

@@ -303,12 +303,12 @@ remove_temp(void)
  * Signal handler that calls remove_temp() and reraises the signal.
  */
 static void
-signal_remove_temp(int signum)
+signal_remove_temp(SIGNAL_ARGS)
 {
 	remove_temp();
 
-	pqsignal(signum, SIG_DFL);
+	pqsignal(postgres_signal_arg, SIG_DFL);
-	raise(signum);
+	raise(postgres_signal_arg);
 }
 
 /*