libm math functions are used by lua and NetHack and Lua both need to
link to libdl.a.

Updates to NetHack 3.7 CMakeLists.txt

Be able to carry out uplifts during minor release
lifetimes.

Document a way to be able to uplift struct content
without incrementing EDITLEVEL and breaking existing savefiles.
Use the mechanics outlined to uplift the contents instead, where
it is feasible to do so. The uplift is currently one-way only. An
uplifted savefile cannot be used with an earlier build of NetHack
, one built with a lower SAVEFILE_REVISION_LEVEL, than the one which
wrote the savefile.

The final byte (byte 79) of the 80 critical bytes in the savefile,
of which 10 are reserved for future expansion and not currently
used, will now be used for holding the savefile revision level
(SAVEFILE_REVISION_LEVEL in include/patchlevel.h) at the time
the savefile was written.

That leaves 9 of the bytes available for future use.

The directories and permissions portion of the linux.500 and macOS.500
hints files and their included files has been consolidated to
dirs-perms.500.

The builder can edit that one file now, to identify
the folders that will be utilised as part of the build.

Alternatively, you can set those folders and permissions in a
make.perms file in the top of the NetHack folder tree and
they should take precedence over the ones in dirs-perms.500
because dirs-perms.500 uses '?=' variable assignment, which
means "set the value of the variable if no value has been set."

* NOTE: BUILD CHANGE *

This also makes WANT_SOURCE_INSTALL=1 the default over
WANT_SHARED_INSTALL=1, if neither is explicitly set.
The new default is the safer and less-impacting default,
but it will change where things get installed over earlier
Makefile builds. You can be explicit with WANT_SHARED_INSTALL=1
in your make command to get that..

These are the differences between the two:

make WANT_SHARED_INSTALL=1    Place the results of the install/update portion
                              of the build into a shared area on a multiuser
                              system.

make WANT_SOURCE_INSTALL=1    Place the results of the install/update portion
                              of the build into a subfolder of the source
                              tree, rather than in a system-wide shared area.

Also note that the macOS hints file behaves slightly differntly depending
on whether WANT_SOURCE_INSTALL=1 was set versus letting it be the default.
That's not new, it behaved that way before.

It was using dupstr(), so strutil had to be added to the project.

There is no unintentional spelling mistake.
Close NetHack#1523

…into HEAD

and split out the options into a seperate file
	modified:   CMakeLists.txt
	new file:   CMakeOptions.txt

the resultant binary don't work though
lots done, probably should have split this up into more commits...

important to note is that I changed report.c to not output a backtrace
if NO_BACKTRACE if defined. NO_BACKTRACE gets defined if `backtrace()` is
not defined.

still missing a lot of features that the makefiles have, but it is hard
dechipering the current build system...

	modified:   CMakeLists.txt
	modified:   CMakeOptions.txt
	new file:   src/CMakeLists.txt
	modified:   src/report.c
	new file:   sys/CMakeLists.txt
	modified:   util/CMakeLists.txt
	new file:   win/CMakeLists.txt
	new file:   win/curses/CMakeLists.txt
	new file:   win/tty/CMakeLists.txt

	modified:   CMakeOptions.txt
	modified:   src/CMakeLists.txt
	modified:   sys/CMakeLists.txt
	new file:   sys/share/CMakeLists.txt

just that. added some info on finding config values for cmake too

nethack can run now. requires manual setup of data dirs, but it runs!

next steps: data files (makedefs) and installs