Separate out bgwriter code into a logically separate module, rather

than being random pieces of other files.  Give bgwriter responsibility
for all checkpoint activity (other than a post-recovery checkpoint);
so this child process absorbs the functionality of the former transient
checkpoint and shutdown subprocesses.  While at it, create an actual
include file for postmaster.c, which for some reason never had its own
file before.

src/backend/libpq/pqsignal.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/pqsignal.c,v 1.33 2004/04/12 16:19:18 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/pqsignal.c,v 1.34 2004/05/29 22:48:19 tgl Exp $
  *
  * NOTES
  *		This shouldn't be in libpq, but the monitor and some other
@@ -46,6 +46,17 @@
 #include "libpq/pqsignal.h"
 
 
+#ifdef HAVE_SIGPROCMASK
+sigset_t	UnBlockSig,
+			BlockSig,
+			AuthBlockSig;
+#else
+int			UnBlockSig,
+			BlockSig,
+			AuthBlockSig;
+#endif
+
+
 /*
  * Initialize BlockSig, UnBlockSig, and AuthBlockSig.
  *
@@ -153,4 +164,5 @@ pqsignal(int signo, pqsigfunc func)
 	return oact.sa_handler;
 #endif   /* !HAVE_POSIX_SIGNALS */
 }
+
 #endif /* WIN32 */