Use system freetype and fontconfig on linux builds

indra/cmake/FreeType.cmake

 # -*- cmake -*-
 include(Prebuilt)
 
-if (USESYSTEMLIBS)
+if (LINUX OR USESYSTEMLIBS)
   include(FindPkgConfig)
 
   pkg_check_modules(FREETYPE REQUIRED freetype2)
-else (USESYSTEMLIBS)
+  pkg_check_modules(FONTCONFIG REQUIRED fontconfig)
+else ()
   use_prebuilt_binary(freetype)
   set(FREETYPE_INCLUDE_DIRS ${LIBS_PREBUILT_DIR}/include/freetype2/)
   set(FREETYPE_LIBRARIES freetype)
-endif (USESYSTEMLIBS)
+endif ()
 
 link_directories(${FREETYPE_LIBRARY_DIRS})

indra/cmake/ViewerManager.cmake

 include (Prebuilt)
-use_prebuilt_binary(viewer-manager)
-
+if(NOT LINUX)
+    use_prebuilt_binary(viewer-manager)
+endif()

indra/cmake/ViewerMiscLibs.cmake

@@ -4,7 +4,6 @@ include(Prebuilt)
 if (NOT USESYSTEMLIBS)
   if (LINUX)
     use_prebuilt_binary(libuuid)
-    use_prebuilt_binary(fontconfig)
   endif (LINUX)
   use_prebuilt_binary(libhunspell)
   use_prebuilt_binary(slvoice)

indra/llwindow/CMakeLists.txt

@@ -73,11 +73,10 @@ if (LINUX)
       ${LLMATH_LIBRARIES}
       ${LLRENDER_LIBRARIES}
       ${LLVFS_LIBRARIES}
-      ${LLWINDOW_LIBRARIES}
       ${LLXML_LIBRARIES}
       ${UI_LIBRARIES}     # for GTK
       ${SDL_LIBRARY}
-      fontconfig          # For FCInit and other FC* functions.
+      ${FONTCONFIG_LIBRARIES}          # For FCInit and other FC* functions.
       )
 
   list(APPEND viewer_SOURCE_FILES