fix: If documentation added, then need cache type

Templates/CMakeSystemConfig.cmake.in

@@ -2,7 +2,7 @@
 # CMakeLocal.make.in should be in the directory where you run configure
 # in, which need not be the source directory
 #
-SET (CMAKE_WORDS_BIGENDIAN    @CMAKE_WORDS_BIGENDIAN@
+SET (CMAKE_WORDS_BIGENDIAN    @CMAKE_WORDS_BIGENDIAN@ CACHE BOOL 
      "Byte ordering is big-endian.")
 
 SET (CMAKE_USE_SPROC          @CMAKE_USE_SPROC@ CACHE BOOL