This semantic is used in make-reg-dotc (the shell script) as well and it
is needed, if the source directory and the build directory are different.
svn path=/trunk/; revision=8057
script 'make-reg-dotc'. It is used only in the Win32 build because the
make-reg-dotc shell script is *so* sloooooooooow on Win32, due to the
multiple processes (grep, grep, sed) launched multiple times for each
source file. By putting all the text-mangling logic into a single Python
script, only one process is launched, and the source files are read
only once. It's *a lot* faster... seconds instead of minutes.
svn path=/trunk/; revision=2873