Environment variables not documented in README:

The default (when none of these variables is set) is used to develop
BabyChess.  ./configure sets them to correct values for installation. 

$build_type
	Determines the build type, possible values are:

        - "":  Build a debug version.  Debugging flags are set for GCC.  All
  	  test programs are compiled. 
	- "optimize":  An optimized version is built.  The macro "NDEBUG" is
  	  defined, and optimization flags are passed to the compiler.   (set by
  	  ./configure) 
	- "none":  Don't define any special macros or flags for compilation. 
	- "profile":  Used for profiling.  Adds "-pg" to the compilation flags
   	  and don't strip symbols. 

$build_once
	Whether a program should be compiled at once or each module
	separately. 

	- "":  Each module is compiled separately into an object file in bin/.
	       All object files are then linked together.  Used for
	       development.  This is faster when recompiling everything when
	       just little has changed in the source. 
	- "1": At once.  Used for fastest compiling.  Files of the form
	       dep/babychess*.cc are produced which include all necessary .cc
	       files in src/.  These files are then compiled at once. 

$build_no_test
	If set, don't compile the test and debug programs (set by ./configure)   

$verbose
	The verbose level.  If empty, be quiet.  Else a number
        indicating the verbosity level.  1 is "normal", 2 is extremely
        verbose.  Set to 1 by ./configure. 

$BABYCHESS_VERSION_NUMBER	
$BABYCHESS_E_MAIL
$BABYCHESS_WEB_SITE
	Set these to change the info displayed by --version and --help.  Used
	at configure time. 


To make a source release:   sh/dist
