Re: [libvirt] AC_HEADER_MAJOR vs. glibc 2.25(-to-be)

Okay, I have confirmed that this prime-the-cache idea DOES work, using libvirt.git commit 419bc8cf (one commit prior to d53fa838 which installed a hack into libvirt to force the use of -Werror for the duration of AC_HEADER_MAJOR [1]). By itself, './configure' succeeds but leaves MAJOR_IN_SYSMACROS undefined, which results in a build failure later in libvirt; but when run as './configure ac_cv_header_sys_types_h_makedev=no', MAJOR_IN_SYSMACROS gets defined and the build succeeds.