[Bug bootstrap] [4.1 regression] Build fails on Cygwin

[THOMAS Paul Richard 169137]

In spite of chanting the incantations given in PR 21766, both a simple make
and a bootstrap fail on Cygwin, with

gcc -c   -g -O2 -DIN_GCC   -W -Wall -Wwrite-strings -Wstrict-prototypes
-Wmissin
g-prototypes -Wmissing-format-attribute -fno-common   -DHAVE_CONFIG_H    -I.
-I.
 -I../../gcc/gcc -I../../gcc/gcc/. -I../../gcc/gcc/../include
-I../../gcc/gcc/..
/libcpp/include -I/usr/local/gmp/include -I/usr/local/gmp/include \
        ../../gcc/gcc/config/i386/i386.c -o i386.o
../../gcc/gcc/config/i386/i386.c: In function `x86_elf_aligned_common':
../../gcc/gcc/config/i386/i386.c:1806: `COMMON_ASM_OP' undeclared (first use
in
this function)
../../gcc/gcc/config/i386/i386.c:1806: (Each undeclared identifier is
reported o
nly once
../../gcc/gcc/config/i386/i386.c:1806: for each function it appears in.)
make[1]: *** [i386.o] Error 1
make[1]: Leaving directory `/cygdrive/d/gcc-cvs/build/gcc'
make: *** [all-gcc] Error 2

COMMON_ASM_OP is defined for other systems but not for i386/winnt.

Paul T