Implement a few changes to how shared libraries and dynamically loadable

modules are built.  Foremost, it creates a solid distinction between these two
types of targets based on what had already been implemented and duplicated in
ad hoc ways before.  Specifically,

- Dynamically loadable modules no longer get a soname.  The numbers previously
set in the makefiles were dummy numbers anyway, and the presence of a soname
upset a few packaging tools, so it is nicer not to have one.

- The cumbersome detour taken on installation (build a libfoo.so.0.0.0 and
then override the rule to install foo.so instead) is removed.

- Lots of duplicated code simplified.

src/backend/utils/mb/conversion_procs/proc.mk

@@ -1,26 +1,17 @@
 SRCS		+= $(NAME).c
 OBJS		+= $(NAME).o
 
-SHLIB_LINK 	:= $(BE_DLLLIBS)
-
-SO_MAJOR_VERSION := 0
-SO_MINOR_VERSION := 0
 rpath =
 
 all: all-shared-lib
 
 include $(top_srcdir)/src/Makefile.shlib
 
-install: all installdirs
-ifeq ($(enable_shared), yes)
-	$(INSTALL_SHLIB) $(shlib) '$(DESTDIR)$(pkglibdir)/$(NAME)$(DLSUFFIX)'
-endif
+install: all installdirs install-lib
 
-installdirs:
-	$(mkinstalldirs) '$(DESTDIR)$(pkglibdir)'
+installdirs: installdirs-lib
 
-uninstall:
-	rm -f '$(DESTDIR)$(pkglibdir)/$(NAME)$(DLSUFFIX)'
+uninstall: uninstall-lib
 
 clean distclean maintainer-clean: clean-lib
 	rm -f $(OBJS)