Compile broker against pthreads if threading enabled.

This allows plugins to *carefully* use threads.

CMakeLists.txt

@@ -71,7 +71,7 @@ option(WITH_SRV "Include SRV lookup support?" OFF)
 option(WITH_STATIC_LIBRARIES "Build static versions of the libmosquitto/pp libraries?" OFF)
 option(WITH_PIC "Build the static library with PIC (Position Independent Code) enabled archives?" OFF)
 
-option(WITH_THREADING "Include client library threading support?" ON)
+option(WITH_THREADING "Include threading support?" ON)
 if(WITH_THREADING)
 	add_definitions("-DWITH_THREADING")
 endif()

apps/mosquitto_ctrl/CMakeLists.txt

@@ -65,6 +65,14 @@ if(WITH_TLS AND CJSON_FOUND)
 		${CJSON_LIBRARIES}
 	)
 
+	if (WITH_THREADING AND NOT WIN32)
+		set(THREADS_PREFER_PTHREAD_FLAG ON)
+		find_package(Threads REQUIRED)
+
+		target_link_libraries(mosquitto_ctrl PRIVATE Threads::Threads)
+	endif()
+
+
 	install(TARGETS mosquitto_ctrl
 		RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
 	)

config.mk

@@ -269,6 +269,8 @@ ifeq ($(WITH_TLS),yes)
 endif
 
 ifeq ($(WITH_THREADING),yes)
+	BROKER_CFLAGS:=$(BROKER_CFLAGS) -pthread
+	BROKER_LDFLAGS:=$(BROKER_LDFLAGS) -pthread
 	LIB_CFLAGS:=$(LIB_CFLAGS) -pthread
 	LIB_CPPFLAGS:=$(LIB_CPPFLAGS) -DWITH_THREADING
 	LIB_LDFLAGS:=$(LIB_LDFLAGS) -pthread

src/CMakeLists.txt

@@ -240,6 +240,13 @@ target_link_libraries(mosquitto
 	${MOSQ_LIBS}
 )
 
+if (WITH_THREADING AND NOT WIN32)
+	set(THREADS_PREFER_PTHREAD_FLAG ON)
+	find_package(Threads REQUIRED)
+
+	target_link_libraries(mosquitto PRIVATE Threads::Threads)
+endif()
+
 if(WIN32)
 	set_target_properties(mosquitto PROPERTIES
 		ENABLE_EXPORTS 1