diff -upr orig/gdb-7.5.1/bfd/config.bfd gdb-7.5.1/bfd/config.bfd
--- orig/gdb-7.5.1/bfd/config.bfd	2012-05-15 21:55:34.000000000 +0900
+++ gdb-7.5.1/bfd/config.bfd	2013-03-02 13:51:33.231615500 +0900
@@ -633,7 +633,7 @@ case "${targ}" in
     targ_archs="$targ_archs bfd_arm_arch"
     want64=true
     ;;
-  x86_64-*-mingw* | x86_64-*-pe | x86_64-*-pep)
+  x86_64-*-mingw* | x86_64-*-pe | x86_64-*-pep | x86_64-*-cygwin*)
     targ_defvec=x86_64pe_vec
     targ_selvecs="x86_64pe_vec x86_64pei_vec bfd_elf64_x86_64_vec bfd_elf64_l1om_vec bfd_elf64_k1om_vec i386pe_vec i386pei_vec bfd_elf32_i386_vec"
     want64=true
Only in gdb-7.5.1/gdb/config/i386: cygwin64.mh
diff -upr orig/gdb-7.5.1/gdb/configure.host gdb-7.5.1/gdb/configure.host
--- orig/gdb-7.5.1/gdb/configure.host	2012-05-31 04:41:34.000000000 +0900
+++ gdb-7.5.1/gdb/configure.host	2013-03-02 13:56:23.221202000 +0900
@@ -178,6 +178,9 @@ x86_64-*-openbsd*)	gdb_host=obsd64 ;;
 x86_64-*-mingw*)        gdb_host=mingw64
 			gdb_host_obs=mingw-hdep.o
 			;;
+x86_64-*-cygwin*)        gdb_host=cygwin64
+			#gdb_host_obs=cygwin-hdep.o
+			;;
 m32r*-*-linux*)          gdb_host=linux ;;
 
 xtensa*-*-linux*)	gdb_host=linux ;;
diff -upr orig/gdb-7.5.1/gdb/configure.tgt gdb-7.5.1/gdb/configure.tgt
--- orig/gdb-7.5.1/gdb/configure.tgt	2012-08-02 04:48:44.000000000 +0900
+++ gdb-7.5.1/gdb/configure.tgt	2013-03-02 13:54:17.692022100 +0900
@@ -608,7 +608,7 @@ x86_64-*-freebsd* | x86_64-*-kfreebsd*-g
 			i387-tdep.o i386bsd-tdep.o i386fbsd-tdep.o \
 			bsd-uthread.o solib-svr4.o"
 	;;
-x86_64-*-mingw*)
+x86_64-*-mingw* | x86_64-*-cygwin* )
         # Target: MingW/amd64
 	gdb_target_obs="amd64-tdep.o amd64-windows-tdep.o \
                         i386-tdep.o i386-cygwin-tdep.o i387-tdep.o \
diff -upr orig/gdb-7.5.1/gdb/gdbserver/configure.srv gdb-7.5.1/gdb/gdbserver/configure.srv
--- orig/gdb-7.5.1/gdb/gdbserver/configure.srv	2012-05-31 04:43:15.000000000 +0900
+++ gdb-7.5.1/gdb/gdbserver/configure.srv	2013-03-02 14:19:58.084127500 +0900
@@ -305,6 +305,11 @@ case "${target}" in
 			srv_xmlfiles="$srv_i386_xmlfiles $srv_amd64_xmlfiles"
 			srv_mingw=yes
 			;;
+  x86_64-*-cygwin*)	srv_regobj="$srv_amd64_regobj"
+			srv_tgtobj="i386-low.o i387-fp.o win32-low.o win32-i386-low.o"
+			srv_xmlfiles="$srv_i386_xmlfiles $srv_amd64_xmlfiles"
+			srv_mingw=yes
+			;;
 
   xtensa*-*-linux*)	srv_regobj=reg-xtensa.o
 			srv_tgtobj="linux-low.o linux-osdata.o linux-xtensa-low.o linux-procfs.o"