You can try to use
WideCharToMultiByte()
to convert the strings to ASCII using precomposed characters and compare the converted ASCII strings:
char lpszAscii[128];
::WideCharToMultiByte(20127, WC_COMPOSITECHECK, L"Dušan áíéúó", -1, lpszAscii, 128, NULL, NULL);
int nCompare = stricmp(lpszAscii, "Dusan aieuo")
But note that this fails for some characters and all symbols (will be replaced by a '?'). Examples are the German 'ß' and currency symbols like '€'. If you are limited to code page 1250, you may check all characters from this code page and provide special handling for the characters that fail (e.g. replace the Euro symbol by 'EUR').