package/gdb: fix gnulib issue with musl and uClibc toolchains (finally)

The previous fix [1] reinroduced the issue fixed by [2].
So keep gl_cv_func_gettimeofday_clobber=no in GDB_CONF_ENV
and GDB_MAKE_ENV.

Fixes:
http://autobuild.buildroot.net/results/ec6/ec60d436bd34a4f37b664e4124d7f0c96e90a1be

[1] faf38b78aee613a732f96d5022a2894efd024a25
[2] 560334bb2a46a77081a3944d092df7732dfca432

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit 2530fe810ee7ece8da30e246af522e2e0be8e83f)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdb/gdb.mk

@@ -84,9 +84,11 @@ GDB_CONF_ENV = \
 # not when cross-compiling with uClibc or musl as C libraries. So use
 # gl_cv_func_gettimeofday_clobber=no to not use rpl_gettimeofday,
 # assuming musl and uClibc have a properly working gettimeofday
-# implementation. It needs to be passed to GDB_MAKE_ENV and not
-# GDB_CONF_ENV, because otherwise it does not get passed to the
-# configure script of nested packages.
+# implementation. It needs to be passed to GDB_CONF_ENV to build
+# gdbserver only but also to GDB_MAKE_ENV, because otherwise it does
+# not get passed to the configure script of nested packages while
+# building gdbserver with full debugger.
+GDB_CONF_ENV += gl_cv_func_gettimeofday_clobber=no
 GDB_MAKE_ENV = gl_cv_func_gettimeofday_clobber=no
 
 # The shared only build is not supported by gdb, so enable static build for