VWR-8885 CMAKE build hard depends on artwork files

Warn earlier, clearer and harder about missing artwork bundle - this still bites snowglobe builders regularly.
Reviewed by Aimee.

indra/cmake/ViewerMiscLibs.cmake

@@ -7,3 +7,10 @@ if (NOT STANDALONE)
   use_prebuilt_binary(fontconfig)
 endif(NOT STANDALONE)
 
+if(VIEWER AND NOT STANDALONE)
+  if(EXISTS ${CMAKE_SOURCE_DIR}/newview/res/have_artwork_bundle.marker)
+    message(STATUS "We seem to have an artwork bundle in the tree - brilliant.")
+  else(EXISTS ${CMAKE_SOURCE_DIR}/newview/res/have_artwork_bundle.marker)
+    message(FATAL_ERROR "Didn't find an artwork bundle - this needs to be downloaded separately and unpacked into this tree.  You can probably get it from the same place you got your viewer source.  Thanks!")
+  endif(EXISTS ${CMAKE_SOURCE_DIR}/newview/res/have_artwork_bundle.marker)
+endif(VIEWER AND NOT STANDALONE)

indra/newview/ViewerInstall.cmake

@@ -7,8 +7,8 @@ install(DIRECTORY skins app_settings linux_tools
         PATTERN ".svn" EXCLUDE
         )
 
-find_file(IS_ARTWORK_PRESENT NAMES avatar_lad.xml
-          PATHS ${VIEWER_DIR}/newview/character)
+find_file(IS_ARTWORK_PRESENT NAMES have_artwork_bundle.marker
+          PATHS ${VIEWER_DIR}/newview/res)
 
 if (IS_ARTWORK_PRESENT)
   install(DIRECTORY res res-sdl character

indra/newview/res/have_artwork_bundle.marker

+If this file exists then you have the artwork bundle installed, which is packaged separately from the Viewer source in the open-source tree.  This marker is for the benefit of the build system so it can warn you properly if it's not there. :)