[RFC]: Move __CYGWIN__ hack to config/<arch>/xm-cygwin.h

[jtc@redback.com (J.T. Conklin)]

I found some code in defs.h that defines __CYGWIN__ if __CYGWIN32__ is
defined (if it is not already defined).  While I admit that defs.h has
it's fair share of hacks they are more general (for the most part, they
add definitions missing from older UN*X systems (SEEK_SET, STDIN_FILENO,
etc.).  IMO, this code belongs in a cygwin host header file.

The enclosed patch moves it from defs.h to config/i386/xm-cygwin.h and
config/powerpc/xm-cygwin.h.  It seems to me there is enough duplication
in those two headers that a common config/xm-cygwin.h header is justified,
but I'll leave that to cygwin hackers to deal with.

Thoughts?

        --jtc

2001-03-01  J.T. Conklin  <jtc@redback.com>

	* defs.h (__CYGWIN__): Moved conditional which defines __CYGWIN__
 	if __CYGWIN32__ is set from here.
	* config/i386/xm-cygwin.h: To here.
	* config/powerpc/xm-cygwin.h: To here.
Index: defs.h
===================================================================
RCS file: /cvs/src/src/gdb/defs.h,v
retrieving revision 1.38
diff -c -r1.38 defs.h
*** defs.h	2001/02/08 06:49:19	1.38
--- defs.h	2001/03/02 02:07:01
***************
*** 1259,1272 ****
  #define MERGEPID(PID, TID) (PID)
  #endif
  
- /* If under Cygwin, provide backwards compatibility with older
-    Cygwin compilers that don't define the current cpp define. */
- #ifdef __CYGWIN32__
- #ifndef __CYGWIN__
- #define __CYGWIN__
- #endif
- #endif
- 
  /* Define well known filenos if the system does not define them.  */
  #ifndef STDIN_FILENO
  #define STDIN_FILENO   0

-- 
J.T. Conklin
RedBack Networks