Ports: Add initial GDB 11.1 port

This builds and runs, but crashes when you attempt to try to debug
something at the moment.

Ports/gdb/patches/build-config.patch

@@ -0,0 +1,55 @@
+diff --git a/bfd/config.bfd b/bfd/config.bfd
+index 30087e3..11dc114 100644
+--- a/bfd/config.bfd
++++ b/bfd/config.bfd
+@@ -634,6 +634,11 @@ case "${targ}" in
+     targ_selvecs=
+     targ64_selvecs=x86_64_elf64_vec
+     ;;
++  i[3-7]86-*-serenity*)
++    targ_defvec=i386_elf32_vec
++    targ_selvecs=
++    targ64_selvecs=x86_64_elf64_vec
++    ;;
+ #ifdef BFD64
+   x86_64-*-cloudabi*)
+     targ_defvec=x86_64_elf64_cloudabi_vec
+@@ -694,6 +699,10 @@ case "${targ}" in
+     targ_selvecs=i386_elf32_vec
+     want64=true
+     ;;
++  x86_64-*-serenity*)
++    targ_defvec=x86_64_elf64_vec
++    want64=true
++    ;;
+ #endif
+   i[3-7]86-*-lynxos*)
+     targ_defvec=i386_elf32_vec
+diff --git a/gdbsupport/configure b/gdbsupport/configure
+index a9dd02c..3c5bcf5 100755
+--- a/gdbsupport/configure
++++ b/gdbsupport/configure
+@@ -8934,7 +8934,7 @@ $as_echo "$gdb_cv_cxx_std_thread" >&6; }
+ 
+     # This check must be here, while LIBS includes any necessary
+     # threading library.
+-    for ac_func in pthread_sigmask pthread_setname_np
++    for ac_func in pthread_setname_np
+ do :
+   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
+ ac_fn_cxx_check_func "$LINENO" "$ac_func" "$as_ac_var"
+diff --git a/libiberty/configure b/libiberty/configure
+index fffb91d..defc239 100755
+--- a/libiberty/configure
++++ b/libiberty/configure
+@@ -6478,7 +6478,9 @@ case "${host}" in
+     $as_echo "#define HAVE_SYS_ERRLIST 1" >>confdefs.h
+ 
+     $as_echo "#define HAVE_SYS_NERR 1" >>confdefs.h
+-
++    ;;
++  *-*-serenity*)
++    $as_echo "#define HAVE_PSIGNAL 1" >>confdefs.h
+     ;;
+ esac
+