I've just tried to build libmcrypt 2.5.8 on Solaris 10 update 3, with all patches until February, and using the Studio 12 compilers. The build fails with the message "error: C++ compiler cannot create executables". I tried compiling 2.5.7 in exactly the same environment, which ran through without problems. A complete history of the builds is attached.
text file containing build history from 2.5.7 and 2.5.8