AC_HELP_STRING([--with-nvcontrol=nvcontrol-dir],[uses libXNVCtrl.a instead of nvidia-settings for the NVidia thermal source]),
[with_nvcontrol=yes
nvcontrol_CFLAGS=-I$withval
nvcontrol_LIBS="-L$withval -lXNVCtrl"
AC_CHECK_FILE([$withval/NVCtrlLib.h], , AC_MSG_ERROR([Did not find NVCtrlLib.h. Make sure that you passed the correct path for NVControl. See README for details.]))
AC_DEFINE(HAVE_NVCONTROL, , [defined if compiling with NVControl support])])