>> Add the following line at the top of mono/configure.in: >> AC_PREREQ(2.13) > This shouldnt be necessary... According to autoconf-wrapper readme from Cygwin, this may be necessary if you have 2.13 and 2.5x installed side-by-side and want to use stable version. That's Cygwin specific anyway. That said I have no problems with 2.52 Sergey