* gnu/packages/patches/gdb-hurd64.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/gdb.scm (gdb-15): Use it in new variable.
(gdb-minmal-15): New variable.
(gdb/pinned): When building for the 64bit Hurd, set #:configure-flags to
"--enable-targets=i586-pc-gnu,x86_64-pc-gnu".
Change-Id: I52d28092be6c415b8668bb5a77d41c87df841351
