Cygwin build from source is broken since binutils-2.42-1

[Christian Franke]

This is not a binutils regression: A build from cygwin 3.5.0-1 src 
package or current newlib-cygwin git main (bfb68a9) with new 
binutils-2.42-1 fails with:

"
In file included from ../../../../winsup/utils/dumper.cc:23:
/usr/include/bfd.h:2748:1: error: expected initializer before 
‘ATTRIBUTE_WARN_UNUSED_RESULT’
"

Downgrading to binutils 2.41-3 fixes the problem.

A diff of /usr/include/bsd.h shows that ATTRIBUTE_WARN_UNUSED_RESULT is 
a new addition in 2.42-1. This requires /usr/include/ansidecl.h. It is 
included by /usr/include/bsd.h but this has no effect because Cygwin 
source tree provides its own ansidecl.h which lacks 
ATTRIBUTE_WARN_UNUSED_RESULT:

$ g++ ....MANY_OPTIONS... -E ../../../../winsup/utils/dumper.cc
...
# 1 "../../../../winsup/utils/dumper.cc"
...
# 1 "../../../../winsup/../include/ansidecl.h" 1  <== #define _ANSIDECL_H
...
# 1 "/usr/include/bfd.h" 1 3 4
...
# 1 "/usr/include/ansidecl.h" 1 3 4  <== #ifndef _ANSIDECL_H
...

-- 
Regards,
Christian