alpha-openbsd build failure

[Alan Modra]

This target doesn't build, due to a missing gas/config/te-obsd.h file.
It's been that way since the commit switching to elf, in 2002.
https://lists.gnu.org/archive/html/bug-gnu-utils/2002-07/msg00128.html

	* configure.tgt (alpha-*-openbsd*): Use em=nbsd.

diff --git a/gas/configure.tgt b/gas/configure.tgt
index eda38a2..cda0e26 100644
--- a/gas/configure.tgt
+++ b/gas/configure.tgt
@@ -127,8 +127,7 @@ case ${generic_target} in
   alpha-*-osf*)				fmt=ecoff ;;
   alpha-*-linux*ecoff*)			fmt=ecoff ;;
   alpha-*-linux-*)			fmt=elf em=linux ;;
-  alpha-*-netbsd*)			fmt=elf em=nbsd ;;
-  alpha-*-openbsd*)			fmt=elf em=obsd ;;
+  alpha-*-netbsd* | alpha-*-openbsd*)	fmt=elf em=nbsd ;;
 
   arc-*-elf*)				fmt=elf ;;
   arc*-*-linux*)			fmt=elf bfd_gas=yes ;;

-- 
Alan Modra
Australia Development Lab, IBM