Details on rebuilding specific platforms and features are shown below. See the manual Rebuilding From Source for detailed instructions.
Some general notes:
progressive-95q1 release.  As of 
progressive-95q4, we have fixed the configuration scheme so that 
GDBTK (and the rest of the CDK) should build without any other 
problems with regard to X Windows.
The configuration scheme will try to find your X libraries and include
files by first running the program `xmkmf'.  If that fails for any
reason, it should look through a long list of probable directories to
find the lib and include directories.
If all of this fails, you can specify the location of your X libraries
and include files with the --x-includes=/some/where and
--x-libraries=/some/where command line options at configure-time.
If you do not have X Windows on your Unix system, configure with
the option --without-x.
--enable-gdbtk on the command line to
configure. 
Note: Using `--enable-gdbtk' when rebuilding under Solaris or
HPUX is known to fail.  Contact Cygnus for an available patch if this is
a problem for you.  (Reference PR #6743)
configure with the option --with-stabs when
rebuilding the CDK under SGI/Irix4 and Irix5 as well as on the
Alpha running OSF/1 v2.0.
configure in the background; when configuring
the program expect, configure hangs with a terminal
message similar to the following:
checking mask type of select checking return type of signal handlers checking to see if signals need to be re-armed checking whether cross-compiling... no checking to see if stty reads from stdin or stdout [1] + Suspended (tty output) ../progressive/configu\ re --prefix=`pwd`/stage1 -v |& tee config.outat which point the shell waits for you to put the process in the foreground again.
Please report any problems you have with building under
progressive-95q4.
--with-gnu-as when configuring MIPS