Use the find_dependency option to parse Simgear dependencies to FlightGear

CMakeLists.txt

@@ -211,11 +211,10 @@ else()
 endif(ENABLE_RTI)
 
 if(ENABLE_CYCLONE)
-    if (NOT TARGET CycloneDDS::ddsc)
     find_package(CycloneDDS QUIET)
-    endif()
     if (CycloneDDS_FOUND)
         message(STATUS "Data Distribution Service support: CycloneDDS")
+        set(SG_HAVE_DDS 1)
     else(CycloneDDS_FOUND)
         message(STATUS "Data Distribution Service support: DISBLED")
     endif(CycloneDDS_FOUND)

SimGearConfig.cmake.in

@@ -17,6 +17,12 @@ set(SIMGEAR_SHARED @SIMGEAR_SHARED@)
 
 set(ENABLE_SIMD @ENABLE_SIMD@)
 
+# SycloneDDS support
+set(SG_HAVE_DDS @SG_HAVE_DDS@)
+if(SG_HAVE_DDS)
+    find_dependency(CycloneDDS)
+endif()
+
 # OpenRTI support
 set(ENABLE_RTI @ENABLE_RTI@)
 if(ENABLE_RTI)

simgear/CMakeLists.txt

@@ -131,6 +131,10 @@ install(TARGETS SimGearCore
 # we expose ZLib in some of our headers
 target_link_libraries(SimGearCore PUBLIC ZLIB::ZLIB)
 
+if (SG_HAVE_DDS)
+    target_link_libraries(SimGearCore PRIVATE CycloneDDS::ddsc)
+endif()
+
 if (ENABLE_RTI)
     target_sources(SimGearCore PRIVATE $<TARGET_OBJECTS:rti> $<TARGET_OBJECTS:rti13>)
     target_link_libraries(SimGearCore PRIVATE PkgConfig::RTI)