Move pipe.c into the backend.

It's full of backend-specific error reporting, so it's neither possible
nor necessary for this to be used from frontend code.

src/backend/port/Makefile

@@ -23,6 +23,10 @@ include $(top_builddir)/src/Makefile.global
 
 OBJS = dynloader.o pg_sema.o pg_shmem.o pg_latch.o $(TAS)
 
+ifneq (,$(filter $(PORTNAME),cygwin win32))
+OBJS += pipe.o
+endif
+
 ifeq ($(PORTNAME), darwin)
 SUBDIRS += darwin
 endif

src/backend/port/pipe.c

@@ -10,16 +10,12 @@
  *	must be replaced with recv/send.
  *
  * IDENTIFICATION
- *	  src/port/pipe.c
+ *	  src/backend/port/pipe.c
  *
  *-------------------------------------------------------------------------
  */
 
-#ifndef FRONTEND
 #include "postgres.h"
-#else
-#include "postgres_fe.h"
-#endif
 
 #ifdef WIN32
 int

src/port/Makefile

@@ -34,10 +34,6 @@ OBJS = $(LIBOBJS) chklocale.o dirmod.o exec.o inet_net_ntop.o noblock.o \
 	path.o pgcheckdir.o pgmkdirp.o pgsleep.o pgstrcasecmp.o \
 	qsort.o qsort_arg.o sprompt.o thread.o
 
-ifneq (,$(filter $(PORTNAME),cygwin win32))
-OBJS += pipe.o
-endif
-
 # foo_srv.o and foo.o are both built from foo.c, but only foo.o has -DFRONTEND
 OBJS_SRV = $(OBJS:%.o=%_srv.o)