Due to an announced CERT security vulnerability with sendmail, we recently ported the latest version of sendmail (8.12.9) to QNX 4 using the TCP/IP 5.0 libraries. Now we are willing to provide the compiled files to other QNX 4 users, but no warranty comes with these files. 
The new files are located at home.insightbb.com/~toncor/qnx4/ … dmail.html if you are interested in using them.
Good Luck!