travis: Re-add libglew dependency
Needed by engine in C port.
if(UNIX AND NOT APPLE)
configure_file(hwengine.desktop.in hwengine.desktop)
file(GLOB miscfiles *.xml *.desktop)
install(FILES ${miscfiles} DESTINATION ${SHAREPATH}/Data/misc)
install(FILES hedgewars.xpm DESTINATION ${CMAKE_INSTALL_PREFIX}/share/pixmaps)
endif()