if(NOT LIBUNWIND_INCLUDE_DIR)
message(WARNING "failed to find libunwind.h")
set(LIBUNWIND_FOUND "")
-elif(NOT EXISTS "${LIBUNWIND_INCLUDE_DIR}/unwind.h")
+elseif(NOT EXISTS "${LIBUNWIND_INCLUDE_DIR}/unwind.h")
message(WARNING "libunwind.h was found, but unwind.h was not found in that directory.")
set(LIBUNWIND_FOUND "")
SET(LIBUNWIND_INCLUDE_DIR "")