Add a "unity" param to add_module

* Turns out that target properties don't propagate to dependents the way
  compile definitions and options do.

cmake/RippledCore.cmake

@@ -70,35 +70,35 @@ include(add_module)
 include(target_link_modules)
 
 # Level 01
-add_module(xrpl beast)
+add_module(xrpl beast ${unity})
 target_link_libraries(xrpl.libxrpl.beast PUBLIC
   xrpl.imports.main
   xrpl.libpb
 )
 
 # Level 02
-add_module(xrpl basics)
+add_module(xrpl basics ${unity})
 target_link_libraries(xrpl.libxrpl.basics PUBLIC xrpl.libxrpl.beast)
 
 # Level 03
-add_module(xrpl json)
+add_module(xrpl json ${unity})
 target_link_libraries(xrpl.libxrpl.json PUBLIC xrpl.libxrpl.basics)
 
-add_module(xrpl crypto)
+add_module(xrpl crypto ${unity})
 target_link_libraries(xrpl.libxrpl.crypto PUBLIC xrpl.libxrpl.basics)
 
 # Level 04
-add_module(xrpl protocol)
+add_module(xrpl protocol ${unity})
 target_link_libraries(xrpl.libxrpl.protocol PUBLIC
   xrpl.libxrpl.crypto
   xrpl.libxrpl.json
 )
 
 # Level 05
-add_module(xrpl resource)
+add_module(xrpl resource ${unity})
 target_link_libraries(xrpl.libxrpl.resource PUBLIC xrpl.libxrpl.protocol)
 
-add_module(xrpl server)
+add_module(xrpl server ${unity})
 target_link_libraries(xrpl.libxrpl.server PUBLIC xrpl.libxrpl.protocol)
 
 

cmake/add_module.cmake

@@ -9,12 +9,15 @@ include(isolate_headers)
 # that cannot include headers from other directories in include/
 # unless they come through linked libraries.
 #
-# add_module(parent a)
-# add_module(parent b)
+# add_module(parent a true)
+# add_module(parent b false)
 # target_link_libraries(project.libparent.b PUBLIC project.libparent.a)
-function(add_module parent name)
+function(add_module parent name unity)
   set(target ${PROJECT_NAME}.lib${parent}.${name})
   add_library(${target} OBJECT)
+  if(unity)
+    set_target_properties(${target} PROPERTIES UNITY_BUILD ON)
+  endif()
   file(GLOB_RECURSE sources CONFIGURE_DEPENDS
     "${CMAKE_CURRENT_SOURCE_DIR}/src/lib${parent}/${name}/*.cpp"
   )