You can't; MinGW links the scanf() function from the MSVC runtime (msvcrt*.dll), for which the source is not available.
You can't. But FYI&F: there are sources for some of microsoft crt routines in MSVCDIR\Vc7\crt\ or so (if you have msvc installed and "install crt sources" option enabled)
Interesting thing is "strlen.asm" - it works fine, but i couldn't understand it (may be because of mental forces degradation due to my university studies).
After that thing I strongly respect microsoft guys.