Fix scope on preprocessor variables for Max plugin.

plAudioCore needs to know whether we intend to build the plugin, so
the change introduced in 978edc1 was causing compilation to fail when
building the plugin.

This moves detection and definition back into the root CMakeList,
but preserves the behavior of only looking for the SDK if needed.

CMakeLists.txt

@@ -100,6 +100,12 @@ option(PLASMA_BUILD_RESOURCE_DAT "Do we want to build resource.dat?" ON)
 option(PLASMA_BUILD_LAUNCHER "Do we want to build plUruLauncher?" ON)
 option(PLASMA_BUILD_TOOLS "Do we want to build the Plasma tools?" ON)
 
+option(3dsm_BUILD_PLUGIN "Do we want to build the 3ds Max plugin?" OFF)
+if(3dsm_BUILD_PLUGIN)
+    find_package(MaxSDK REQUIRED)
+    add_definitions(-DBUILDING_MAXPLUGIN)
+endif(3dsm_BUILD_PLUGIN)
+
 option(USE_VLD "Build and link with Visual Leak Detector (MSVC only)" OFF)
 if(USE_VLD)
     add_definitions(-DUSE_VLD)

Sources/Tools/CMakeLists.txt

@@ -8,12 +8,7 @@ if(PLASMA_BUILD_TOOLS)
 endif()
 
 # Max Stuff goes below here...
-option(3dsm_BUILD_PLUGIN "Do we want to build the 3ds Max plugin?" OFF)
 if(3dsm_BUILD_PLUGIN)
-    find_package(MaxSDK REQUIRED)
-    add_definitions(-DBUILDING_MAXPLUGIN)
-    add_definitions(-DMAXPLUGINCODE)
-
     add_subdirectory(MaxComponent)
     add_subdirectory(MaxConvert)
     add_subdirectory(MaxExport)