package/gdb: Remove special handling of libstdc++ for ARC

Effectively that's a revert of a very old fix [1]
which is no longer needed.

[1] https://git.buildroot.net/buildroot/commit/?id=ca99d0ea925e5a8e42bd270402b0171a39d1d955

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 7077476c8c85f23897ce14a203cc91596a63b202)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdb/gdb.mk

@@ -171,13 +171,6 @@ else
 GDB_CONF_OPTS += --disable-gdbserver
 endif
 
-# When gdb is built as C++ application for ARC it segfaults at runtime
-# So we pass --disable-build-with-cxx config option to force gdb not to
-# be built as C++ app.
-ifeq ($(BR2_arc),y)
-GDB_CONF_OPTS += --disable-build-with-cxx
-endif
-
 # gdb 7.12+ by default builds with a C++ compiler, which doesn't work
 # when we don't have C++ support in the toolchain
 ifneq ($(BR2_INSTALL_LIBSTDCPP),y)