Enable -fPIC option when building static mosquitto

When linking static mosquitto into shared mqtt, we need static mosquitto
to be built with -fPIC option enabled

Author: RunsFor

mqtt/CMakeLists.txt

@@ -7,6 +7,7 @@ option(WITH_STATIC_LIBRARIES "Build static versions of the libmosquitto/pp libra
 
 if( STATIC_BUILD )
 	set(WITH_STATIC_LIBRARIES ON)
+	set(WITH_PIC ON)
 	set(OPENSSL_USE_STATIC_LIBS ON)
 endif()