The Makefile targets for crosscompiling MIDAS are now documented in the MIDAS
Doxygen documentation:

make linux32 & make clean32
make linux64 & make clean64
make crosscompile
make dox

This has to do with which flavour of MIDAS is built by default: 32-bit or 64-bit.

This is how this works now.

Default flavour is determined by ROOT. If ROOTSYS points to 32-bit ROOT, then
32-bit MIDAS is built, if 64-bit ROOT, then 64-bit MIDAS. This works well after
the ROOT team added the correct "-m32" and "-m64" flags to "rootconfig --cflags".

If for some reason, we also need a non-default flavour of MIDAS, for example
when the main daq computer runs 64-bit MIDAS, but one frontend has to run on a
"32-bit only" VME processor, you say "make linux32". This creates the
"linux-m32/{lib,bin}" tree that you then reference in the Makefile of your
special frontend (i.e. instead of "-L$MIDASSYS/linux/lib" say
"-L$MIDASSYS/linux-m32/lib"). "make linux64" works the same way.

These non-default flavours of MIDAS are compiled with most special features
disabled: no ROOT, no MYSQL, etc.

When building "make linux32", you may also see errors caused by missing 32-bit
libraries - many 64-bit Linux distributions do not install the full 32-bit
development environment by default - so some header files and libraries may be
reported as missing. These not-installed-by-default 32-bit packages are usually
easy to install using commands like "yum install libxxx-devel.i386".

K.O.