Fix #718, add user-specified extra modules to build

Add a new setting that can be set in targets.cmake, to
enable users to add extra custom functions/modules to
CFE core itself.

This can be used, among other things, for future support
of a modular/customizable message header structure.

cmake/mission_build.cmake

@@ -127,7 +127,7 @@ function(prepare)
   # so this is run in a loop until the list of unfound apps is empty
   string(REPLACE ":" ";" CFS_APP_PATH "$ENV{CFS_APP_PATH}")
   list(APPEND CFS_APP_PATH "apps" "apps/CFS" "libs" "psp/fsw/modules")
-  set(MISSION_DEPS "cfe-core" "osal")
+  set(MISSION_DEPS "cfe-core" "osal" ${MISSION_CORE_MODULES})
   set(APP_MISSING_COUNT 0)
 
   # Set the search path of those dependency components which are fixed

cmake/target/CMakeLists.txt

@@ -110,6 +110,7 @@ endif (TGT${TGTID}_APPLIST)
 # This depends on whether any special features are included or not
 set(CFE_LINK_WHOLE_LIBS
     ${CFE_CORE_TARGET}
+    ${MISSION_CORE_MODULES}
     psp-${CFE_SYSTEM_PSPNAME} 
     osal
 )