package/gdb: remove BR2_PACKAGE_GDB_TOPLEVEL

This option was needed to build versions of GDB < 10.x. As we just
dropped support for GDB 9.x, this logic can now be removed.

The special case to configure just gdbserver was only valid for gdb<10,
but was guarded by !GDB_TOPLEVEL (which was equivalent to gdb<10).
GDB_TOPLEVEL is now always true, so we can't hit that special case
anymore.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[yann.morin.1998@free.fr: add little blurb about gdbserver]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/gdb/Config.in.host

@@ -67,14 +67,3 @@ config BR2_GDB_VERSION
 	default "11.2"     if BR2_GDB_VERSION_11 || !BR2_PACKAGE_HOST_GDB
 	default "12.1"     if BR2_GDB_VERSION_12
 	depends on BR2_PACKAGE_GDB || BR2_PACKAGE_HOST_GDB
-
-# recent gdb versions (>= 10) have gdbserver moved at the top-level,
-# which requires a different build logic.
-config BR2_PACKAGE_GDB_TOPLEVEL
-	bool
-	default y if BR2_arc
-	default y if BR2_GDB_VERSION_10
-	default y if BR2_GDB_VERSION_11
-	default y if BR2_GDB_VERSION_12
-	default y if !BR2_PACKAGE_HOST_GDB
-	depends on BR2_PACKAGE_GDB || BR2_PACKAGE_HOST_GDB

package/gdb/gdb.mk

@@ -18,23 +18,14 @@ GDB_LICENSE = GPL-2.0+, LGPL-2.0+, GPL-3.0+, LGPL-3.0+
 GDB_LICENSE_FILES = COPYING COPYING.LIB COPYING3 COPYING3.LIB
 GDB_CPE_ID_VENDOR = gnu
 
-# On gdb < 10, if you want to build only gdbserver, you need to
-# configure only gdb/gdbserver.
-ifeq ($(BR2_PACKAGE_GDB_DEBUGGER)$(BR2_PACKAGE_GDB_TOPLEVEL),)
-GDB_SUBDIR = gdb/gdbserver
-
-# When we want to build the full gdb, or for very recent versions of
-# gdb with gdbserver at the top-level, out of tree build is mandatory,
-# so we create a 'build' subdirectory in the gdb sources, and build
-# from there.
-else
+# Out of tree build is mandatory, so we create a 'build' subdirectory
+# in the gdb sources, and build from there.
 GDB_SUBDIR = build
 define GDB_CONFIGURE_SYMLINK
 	mkdir -p $(@D)/$(GDB_SUBDIR)
 	ln -sf ../configure $(@D)/$(GDB_SUBDIR)/configure
 endef
 GDB_PRE_CONFIGURE_HOOKS += GDB_CONFIGURE_SYMLINK
-endif
 
 # For the host variant, we really want to build with XML support,
 # which is needed to read XML descriptions of target architectures. We