* also check if ECX is nonvolatile in is_ecx_used. Not strictly necessary for the current set of i386 calling conventions, but good as an extra safety precaution in case new calling conventions are added or the code is adapted and used on other platforms.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@25839 3ad0048d-3df7-0310-abae-a5850022a9f2