To "make" correctly version 4.2.2 you need to "make install" previous version of built compiler (/cygwin/usr/local/bin), but not lower than 4.1.0. Compiler complains on unrecognized "-Wc++-compat" which uses in makefile and which seems appeared in the 4.1.0 version. I think this is bug because in "Prerequisites for GCC" nothing said about this kind of requirement.
-- Summary: unrecognized command line option "-Wc++-compat" Product: gcc Version: 4.2.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: bootstrap AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: andry at inbox dot ru GCC host triplet: i686-pc-cygwin http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34414