add linker option for non-executable stack

as well as tests in the configure script for whether the option (and some
others) are accepted by the compiler.

The makefile bin/Makefile.in applies several other compiler flags
that ought to be tested similarly.
Merge branch 'master' of github.com:Macaulay2/M2
add text to INSTALL instructions
stop using the execstack program

since it fails on NFS-mounted file systems, and we now
have a better way to do it with an linker option
update INSTALL instructions
update INSTALL instructions
remove libtool's *.la files after building each package

It seems they just get in the way, as sometimes one version of libtool thinks
the *.la file left by another version of libtool.  We aren't building any
sharable libraries, anyway.
update 4ti2 version and INSTALL instructions

The latest 4ti2 version we use is a temporary beta testing one, provided
to make it compatible with the latest version of glpk.  That will save
us the trouble of building glpk on certain systems.
update INSTALL instructions

to explain what to do on 32 bit systems.

I hope the --build=i686-pc-linux-gnu option is correct -
this may require further experimentation.
my makefiles
update INSTALL instructions

with details about compiling the GNU C compiler from sources
Update INSTALL instructions

... based on experience with SL 6.4.
update INSTALL
update INSTALL
update INSTALL

the package "lapack-devel" should be installed
update INSTALL
git commit QthPower.m2
This is an update of my QthPower package.

It is version 1.02 to replace the existing 0.99.
In it
           weightGrevlex,
           grevlexWeight,
           testWeightMatrix
are now exported, but the undocumented
           polycrt
is no longer exported.
convert an example to a bug report
restore m2/.gdbinit.dan, deleted by mistake