I have sucessfully compiled Stunnel 4.22 on Solaris 10, but still recieve the sam errors during the configure. Initially I tried using Openssl-0.9.8f from Sun Freeware. Then I built and compiled Openssl-0.9.8g, but I still recieved the following errors on the build: configure: **************************************** SSL checking for SSL directory... /usr/local/ssl checking for obsolete RSAref library... no checking /usr/local/ssl/include/openssl/engine.h usability... yes checking /usr/local/ssl/include/openssl/engine.h presence... no configure: WARNING: /usr/local/ssl/include/openssl/engine.h: accepted by the compiler, rejected by the preprocessor! configure: WARNING: /usr/local/ssl/include/openssl/engine.h: proceeding with the compiler's result checking for /usr/local/ssl/include/openssl/engine.h... yes <ftp://ftp.sunfreeware.com/pub/freeware/sparc/10/openssl-0.9.8f-sol10-sparc-local.gz>