unbound: enable SHA1

Fixes the unit test failure about SHA1 being unavailable,
and hopefully the monerod complaints about not being able
to verify DNSSEC.

Thanks to iDunk for the remote Windows testing.

external/unbound/CMakeLists.txt

@@ -53,6 +53,7 @@ add_definitions(-std=c99)
 
 option(USE_ECDSA "Use ECDSA algorithms" ON)
 option(USE_SHA2 "Enable SHA2 support" ON)
+option(USE_SHA1 "Enable SHA1 support" ON)
 set(ENABLE_DNSTAP 0)
 set(HAVE_SSL 1)
 if (CMAKE_USE_PTHREADS_INIT AND NOT CMAKE_USE_WIN32_THREADS_INIT)