If errors compiling using evc "error spawning {cl.exe,clarm.exe}" it may be because you need to be logged in as administrator. Maybe say right from the beginning that it would be wise to be logged in as administrator to avoid random inexplicable failures. apparently one can safely ignore the errors: "could not find the file {mkfuncs.h, psyscall.h, pkfuncs.h}"? before "call patch -p0 --posix < c:\builds\bigpatch", insert the command: touch nsprpub\gmakefile.win at the line "call make -f client.mk build_all" *** * Your source tree contains these files: * /cygdrive/c/builds/wince/mozilla/Makefile * /cygdrive/c/builds/wince/mozilla/config/autoconf.mk * This indicates that you previously built in the source tree. * A source tree build can confuse the separate objdir build. * * To clean up the source tree: * 1. cd /cygdrive/c/builds/wince/mozilla * 2. gmake distclean *** *** Fix above errors and then restart with "make -f client.mk build" make: *** [/cygdrive/c/builds/wince/mozilla/../arm_ppc/Makefile] Error 1 Doing that, I get the error: make: *** No rule to make target `chrome/Makefile.in', needed by `chrome/Makefile'. Stop. Manually deleted those two files and tried again. Got further, but then found error: /cygdrive/c/builds/wince/mozilla/configure: line 3129: syntax error near unexpected token `)' /cygdrive/c/builds/wince/mozilla/configure: line 3129: ` wince*) OS_ARCH=WINCE ;;' *** Fix above errors and then restart with "make -f client.mk build" make: *** [/cygdrive/c/builds/wince/mozilla/../arm_ppc/Makefile] Error 1 At this point I decided to start over.