IFDEF_DESCRIPTION

IFDEFS found in Fortran code
----------------------------

aix - specific to aix in pplus routine cmdini.F to not execute a line of
      code which didn't work on aix systems
AIX_XLF - things specific to usin AIX XLF fortran compiler
atc_gks - specific to commercial atc release of the xgks library
call_handler_each_time - gets defined automatically on solaris and aix 
		         systems - maybe not needed in this list then?
core - pplus only - not sure what it's for - doesn't seem to get used
crptd_cat_argument - sgi only (??) problem w/ appending using "//" in 
		     symbol_command.F
debug_dyn_grids - used only for debugging dynamic grid code
DEC_FORTRAN - items specific to DEC Fortran
F90_DATE_TIME - use the F90 routine date_and_time rather than the 
		f77 routine date.  currently only used for linux
F90_NO_FPUTC - F90 didn't have a "fputc" routine, so had to use a
	       write statement
F90_OPEN_FILE_APPEND - For F90, open files w/ POSITION=APPEND rather
		       than ACCESS=APPEND  
F90_SYSTEM_ERROR_CALLS - Use F90 specific error calls
FORTRAN_90 - General F90 switch
hp - General switch when compiling on HP's
HP_ADDS - Additional needs for HP compilers
inquire_not_nfs_compatible - probably obselete option which was needed when
			     using DEC f772.1 and multinet
MANDATORY_FORMAT_WIDTHS - AIX only - needs explicit format widths
NEED_BYTE - for compilers which user BYTE rather than INTEGER*1
NEED_IAND - for compilers which user intrinsic function IAND 
	    rather than AND 
need_underscore - aix specific - intrinsic function SIGNAL_ needed
		  underscore appended to it. 
NINT_WRITE_UNMATCH - probably obselete switch which was used to isolate
		     an older portion of code which was originally written
		     to fix a VAX bug
NO_ACCESS_APPEND - For compilers whose OPEN statement doesn't 
		   allow ACCESS=APPEND
NO_DOUBLE_ESCAPE_SLASH - for compilers which don't require two
		         backslashes "\\" when escaping the "!" char
NO_OPEN_CARRIAGECONTROL - For compilers whose OPEN statement doesn't 
			  allow CARRIAGECONTROL option
NO_OPEN_READONLY - For compilers whose OPEN statement doesn't 
		   allow READONLY option
NO_OPEN_RECORDTYPE - For compilers whose OPEN statement doesn't 
		     allow RECORDTYPE option
NO_OPEN_SHARED - For compilers whose OPEN statement doesn't 
		 allow SHARED option
NO_PASSED_CONCAT - used when the compiler has a problem passing 
		   concatenated strings to subroutines as arguments
NO_PREPEND_STRING - used for compilers which have a problem prepending
		    strings used in variable assignments
NO_SNGL  - necessary for compilers which do not have the intrinsic 
	   function SNGL
READONLY_ALLOWED - For compiles which allow READONLY in their OPEN
		   statement
reclen_in_bytes - For compilers which use bytes as the default record 
		  length calculator, especially in open statments
sgi  - IRIX specific switch
solaris - Solaris specific switch
STAR_1_SUPPORTED - USed if Integer*1 is supported - used only in pplus 
		   code - same idea as NEED_BYTE
STDERR_UNIT_SEVEN - FOR HP, the stderr unit was 7, instead of 0
sun - sunOS (solaris 1.x) specific switches
ultrix - Ultrix (no longer supported) specific switches
unix - general Unix switch
xgks - Switch to use Xgks
X_REFRESH - For systems which do not have backing store, this Should be 
	    set/used to force screen refreshes of plots


IFDEFS found in C code
-----------------------
BELL - switch to turn on the bell to notify user when X snapshot is
       being taken
CHODEBUG - XGKS debugging switch
DESIGN_TIME -  GUI specific switch - not needed
ESCAPEDEBUG - Another XGKS debugging switch
FULL_GUI_VERSION - Full functionality of GUI - should probably be
		   on by default
HP_SIGNALS - HP specific signal handling
LINK_GUI_AS_MAIN - Link in the gui to Ferret.  W/out this the gui will
		   will not be a part of ferret
MIXING_NAG_F90_AND_C - Needed when using NAG F90 to call some fortran
		       i/o setup routines - necessary w/ c main
		       program
NO_ENTRY_NAME_UNDERSCORES - Whether or not to append an underscore "_"
			    to the name of a subroutine
PSDEBUG - Switch for debugging postscript output
QUERY_DEBUG - Another debugging switch, used in the ferret_query.c routine
SEGMENTDEBUG - Another Xgks debugging switch
SGI_POPUPS - SGI switch in order for menu's to function correctly in GUI
XT_CODE - SWitch to have GUI use Xt library - probably should be default
X_REFRESH - Switch to have set mode refresh on by default - needed on 
	    systems that don't have backing store (ie, SGI)
_NO_PROTO - Switch to allow function prototyping