Fix MsgStream linking in TrigConfBase on Apple

Pushing @akraszna's fix for the linking error, while building TrigConfBase on macOS.

Tested on macOS Mojave 10.14.4.

Cc: @fwinkl

changed the description

This merge request affects 1 package:

• Trigger/TrigConfiguration/TrigConfBase

added Trigger master review-pending-level-1 labels

CI Result SUCCESS

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-23500-2019-05-16-22-25
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST 38580]

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 3c927965

added sweep:ignore label