Building from latest git master does not build winsup... only newlib. Last built a few weeks ago for cpuinfo change testing. But now, even after clearing out, and eventually recreating the build directories, trying relative and absolute configure paths, checking back on the build FAQ, under Cygwin 64 and 32: $ cd ~/src/cygwin/newlib-cygwin/ $ git status On branch master Your branch is up to date with 'origin/master'. nothing to commit, working tree clean $ cd ../build64/ $ ( ../newlib-cygwin/configure -v && make ) &> build64.log & ... $ l -w72 .{,/x86_64-pc-cygwin{,/newlib}} .: build64.log config.status* Makefile x86_64-pc-cygwin/ config.log etc/ serdep.tmp ./x86_64-pc-cygwin: newlib/ ./x86_64-pc-cygwin/newlib: _newlib_version.h libc/ Makefile stmp-targ-include config.cache libc.a multilib.out targ-include/ config.log libg.a newlib.h config.status* libm/ stamp-h1 doc/ libm.a stamp-h2 Sanitized build log attached. Any suggestions for diagnosis or fix? -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]