This directory has a Makefile.lammps file with settings that allows
LAMMPS to dynamically link to the VMD molfile library.  This is
required to use the USER-MOLFILE package and its interface to the dump
and write_dump commands in a LAMMPS input script.

More information about the VMD molfile plugins can be found at
http://www.ks.uiuc.edu/Research/vmd/plugins/molfile.

NOTE: while the programming interface (API) of the VMD molfile plugins
is backward compatible (i.e. you can expect to be able to compile this
package for plugins from newer VMD packages), the binary interface
(ABI) is not.  So it is necessary to compile this package with the
VMD molfile plugin header files (vmdplugin.h and molfile_plugin.h) 
matching VMD installation that the (binary) plugin files are taken from.
These header files can be found inside the VMD installation tree under
"plugins/include". For convenience, this package includes a set of
header files that is compatible with VMD 1.9.3 (the current version
in April 2017). You need to adjust the molfile_SYSINC variable in the
Makefile.lammps file in this directory, in case you want to use VMD
molfile plugins from a different version. The interface is compatible
with plugins starting from VMD version 1.8.4.

In order to be able to dynamically load and execute the plugins from
inside LAMMPS, you need to link with a system library containing functions
like dlopen(), dlsym() and so on for dynamic linking of executable code
into an executable.  This library is defined by setting the molfile_SYSLIB
variable in the Makefile.lammps file in this dir.

For Linux and most current unix-like operating systems, this can be
kept at the default setting of "-ldl" (on some platforms this library
is called "-ldld").  For compilation on Windows, a slightly different
mechanism is used that is part of the Windows programming environment
and this kind of library is not needed.

See the header of Makefile.lammps for more info.