From: Usaku NAKAMURA Date: 2010-06-15T09:19:59+09:00 Subject: [ruby-core:30765] [Bug #3231] Digest Does Not Build Issue #3231 has been updated by Usaku NAKAMURA. In building process, both ext/digest/extconf.h and ext/digest/md5/extconf.h exist. If you specify -I.. in ext/digest/md5 and #include , compiler cannot decide to include whether ext/digest/extconf.h or ext/digest/md5/extconf.h. Gcc gives priority to the place specified by the rear -I, but of course this behavior is not the spec of any standards. It's merely implementation dependence. And, VC10 actually shows different behavior. This is the real problem. My conclusion is that you should specify to complier what do you actually want to include. ---------------------------------------- http://redmine.ruby-lang.org/issues/show/3231 ---------------------------------------- http://redmine.ruby-lang.org