In libpq/Makefile, use OBJS += as a way to break up long link lines into

something that can be documented.

src/interfaces/libpq/Makefile

@@ -29,18 +29,19 @@ endif
 # platforms require special flags.
 LIBS := $(LIBS:-lpgport=)
 
-# 'filter' is used for libpgport C files that are needed by libpq if
-# identified by configure, and we optionally add pgsleep.o below.
 # We can't use Makefile variables here because the MSVC build system scrapes
 # OBJS from this file.
-# The last two lines come from backend/libpq and utils/mb.
 OBJS=	fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
 	fe-protocol2.o fe-protocol3.o pqexpbuffer.o pqsignal.o fe-secure.o \
-	libpq-events.o \
-	inet_net_ntop.o noblock.o pgstrcasecmp.o thread.o \
-	$(filter crypt.o getaddrinfo.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o, $(LIBOBJS)) \
-	ip.o md5.o \
-	encnames.o wchar.o
+	libpq-events.o
+# libpgport C files we always use
+OBJS += inet_net_ntop.o noblock.o pgstrcasecmp.o thread.o
+# libpgport C files that are needed if identified by configure
+OBJS += $(filter crypt.o getaddrinfo.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o, $(LIBOBJS))
+# backend/libpq
+OBJS += ip.o md5.o
+# utils/mb
+OBJS += encnames.o wchar.o
 
 ifeq ($(PORTNAME), cygwin)
 override shlib = cyg$(NAME)$(DLSUFFIX)
@@ -134,9 +135,7 @@ clean distclean: clean-lib
 # Might be left over from a Win32 client-only build
 	rm -f pg_config_paths.h
 	rm -f inet_net_ntop.c noblock.c pgstrcasecmp.c thread.c
-	# optional libpgport files
 	rm -f crypt.c getaddrinfo.c inet_aton.c open.c snprintf.c strerror.c strlcpy.c win32error.c
-	# optional Win32
 	rm -f pgsleep.c	
 	rm -f md5.c ip.c
 	rm -f encnames.c wchar.c