src/poky:glibc: fix C++ compile failures related to 'assert'

* fixes "lambda-expression in unevaluated context" compile failures such as
  nlohmann/json#705

* fixes "no match for 'operator==" compile failures such as
  https://bugzilla.redhat.com/show_bug.cgi?id=1482990

(From OE-Core rev: d9583296be58f02912abc4fd19f576b3f89107ff)

Signed-off-by: S. Lockwood-Childs <sjl@vctlabs.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>