Add pg_upgrade to /contrib; will be in 9.0 beta2.

Add documentation.

Supports migration from PG 8.3 and 8.4.

Author: bmomjian

contrib/pg_upgrade/Makefile

@@ -0,0 +1,30 @@
+#
+# Makefile for pg_upgrade
+#
+#	targets:	all, clean, install, uninstall 
+#
+# This Makefile generates an executable and a shared object file
+#
+
+PROGRAM      = pg_upgrade
+OBJS         = check.o controldata.o dump.o exec.o file.o function.o info.o \
+		option.o page.o pg_upgrade.o relfilenode.o server.o \
+		tablespace.o util.o version.o version_old_8_3.o $(WIN32RES)
+
+PG_CPPFLAGS  = -DFRONTEND -DDLSUFFIX=\"$(DLSUFFIX)\" -I$(srcdir) -I$(libpq_srcdir)
+PG_LIBS      = $(libpq_pgport)
+
+PGFILEDESC   = "pg_upgrade - In-Place Binary Upgrade Utility"
+PGAPPICON    = win32
+MODULES      = pg_upgrade_sysoids
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_upgrade
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif