configure error (warning) - about coffee ???

Got the warning from configure (last line):

checking for getpagesize... yes
checking for working mmap...开发者_C百科 yes
checking for ftruncate... yes
checking for memcmp... yes
checking for memcpy... yes
checking for memmove... yes
checking for memset... yes
checking whether overlapping arrays are copied correctly... yes
checking the coffee machine... empty - operator may not work as expected

What is it about?

Source is a libelf from debian packages.

PS: From configure.in

AC_CACHE_CHECK([the coffee machine], mr_cv_coffee_machine,
  [mr_cv_coffee_machine='empty - operator may not work as expected'])

You forget to switch on the coffee machine or maybe the cable used to operate the machine is broken.

How do you want that all theses script kept working day and night without a good shot of caffeine ?