[PATCH] hurd-amd64 support

[Samuel Thibault]

This adds support for passing -m elf32_x86_64 vs -m elf_x86_64 to the
linker on hurd-amd64

Changelog:

        * m4/libtool.m4: dd x86_64-gnu* case to pass -m elf32_x86_64 vs
        -m elf_x86_64 to linker.

--- m4/libtool.m4.orig  2023-05-03 18:33:23.949698403 +0200
+++ m4/libtool.m4       2023-05-03 18:35:30.760510012 +0200
@@ -1367,7 +1367,7 @@
   ;;
 
 x86_64-*kfreebsd*-gnu|x86_64-*linux*|powerpc*-*linux*| \
-s390*-*linux*|s390*-*tpf*|sparc*-*linux*)
+s390*-*linux*|s390*-*tpf*|sparc*-*linux*|x86_64-gnu*)
   # Find out what ABI is being produced by ac_compile, and set linker
   # options accordingly.  Note that the listed cases only cover the
   # situations where additional linker options are needed (such as when
@@ -1382,7 +1382,7 @@
          x86_64-*kfreebsd*-gnu)
            LD="${LD-ld} -m elf_i386_fbsd"
            ;;
-         x86_64-*linux*)
+         x86_64-*linux*|x86_64-gnu*)
            case `$FILECMD conftest.o` in
              *x86-64*)
                LD="${LD-ld} -m elf32_x86_64"
@@ -1411,7 +1411,7 @@
          x86_64-*kfreebsd*-gnu)
            LD="${LD-ld} -m elf_x86_64_fbsd"
            ;;
-         x86_64-*linux*)
+         x86_64-*linux*|x86_64-gnu*)
            LD="${LD-ld} -m elf_x86_64"
            ;;
          powerpcle-*linux*)