Revert "Remove remainders of HPPA backend"

This reverts commit d41f3c3cc7.

Signed-off-by: Richard Henderson <rth@twiddle.net>

configure

@@ -510,6 +510,8 @@ elif check_define __arm__ ; then
   cpu="arm"
 elif check_define __aarch64__ ; then
   cpu="aarch64"
+elif check_define __hppa__ ; then
+  cpu="hppa"
 else
   cpu=$(uname -m)
 fi
@@ -6107,6 +6109,9 @@ for i in $ARCH $TARGET_BASE_ARCH ; do
   cris)
     disas_config "CRIS"
   ;;
+  hppa)
+    disas_config "HPPA"
+  ;;
   i386|x86_64|x32)
     disas_config "I386"
   ;;