[Plplot-cvs] CVS update notice (plplot)

[Rafael L. <rla...@us...>]

Update of /cvsroot/plplot/plplot
In directory sc8-pr-cvs1:/tmp/cvs-serv21349

Modified Files:
	Makefile.am configure.ac 
Log Message:
Allow use of installed libltdl

A Debian fellow pointed out to me that there is no need to compile the
libltdl support when building the PLplot Debian packages, since there is a
libltdl3 package against which libplplot can be linked.

In order to be able to disable configuration/compilation of the libltdl
support, I did the following changes:

    * In configure.ac, AC_LIBTOOL_CONVENIENCE and AC_LIBTOOL_INSTALLABLE are
      called conditionally on the presence of an installed libltdl (using
      AC_CHECK_LIB).
      
    * In order to avoid config/build of the libltdl directory,
      AC_CONFIG_SUBDIRS(libltdl) is called conditionally as well.  Also, in
      Makefile.am, the libltdl directory is included conditionally on the
      (newly created) AM_CONDITIONAL variable enable_ltdl_convenience.
      [N.B.: I changed the code for setting the SUBDIRS variable in
      Makefile.am using the automake append (+=) operator, instead of using
      the auxiliary variable drivers_src_dirs as before.]

If the user has libltdl installed in the system but wants to use the version
shipped with PLplot, she can override the configure check by giving the
--enable-ltdl-convenience option (this needs further tests, though).

The advantage of using the system's libltdl are:

    * Configuration time is reduced, since the libltdl dir does not need to
      be configured.
    * Build time is also reduced, for a similar reason.
    * The size of the resulting libplplot library is around 10% smaller (at
      least in Linux).