diff -Nau5r barrier-2.3.1/CMakeLists.txt barrier-2.3.1-patched/CMakeLists.txt
--- barrier-2.3.1/CMakeLists.txt	2019-08-09 22:17:30.000000000 +0200
+++ barrier-2.3.1-patched/CMakeLists.txt	2019-09-05 11:41:57.076889377 +0200
@@ -165,11 +165,11 @@
             set (CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -L/usr/local/lib")
             include_directories("/usr/local/include" "/usr/local/include/avahi-compat-libdns_sd")
             link_directories("/usr/local/lib")
         endif()
 
-        if (${PKG_CONFIG_FOUND})
+	if (BARRIER_BUILD_GUI AND ${PKG_CONFIG_FOUND})
             pkg_check_modules (AVAHI_COMPAT REQUIRED avahi-compat-libdns_sd)
             include_directories (BEFORE SYSTEM ${AVAHI_COMPAT_INCLUDE_DIRS})
             set (CMAKE_REQUIRED_INCLUDES "${CMAKE_REQUIRED_INCLUDES};${AVAHI_COMPAT_INCLUDE_DIRS}")
         endif ()