Fix a warning in integration test / gmake / znc-buildmod interaction.
Fix a warning in integration test / gmake / znc-buildmod interaction.

It was requested on https://github.com/gentoo/gentoo/pull/8901

DarthGandalf/znc,markusj/znc,DarthGandalf/znc,markusj/znc,markusj/znc,dgw/znc,psychon/znc,znc/znc,Zarthus/znc,dgw/znc,DarthGandalf/znc,psychon/znc,znc/znc,dgw/znc,psychon/znc,znc/znc,DarthGandalf/znc,DarthGandalf/znc,znc/znc,DarthGandalf/znc,znc/znc,BtbN/znc,BtbN/znc,Zarthus/znc,markusj/znc,dgw/znc,psychon/znc,psychon/znc,BtbN/znc,Zarthus/znc,BtbN/znc,Zarthus/znc,dgw/znc,Zarthus/znc,Zarthus/znc,psychon/znc,markusj/znc,BtbN/znc,dgw/znc,BtbN/znc,znc/znc,markusj/znc