In the 'you didnt think openssl was that insane' series, it tries to use m4 -B 8192 to generate some sparc asm from an m4 file. Unsurprisingly, our m4 doesn't support -B, it's not even in gm4's manpage, and gm4 info page says this about -B : These options are present for compatibility with System V `m4', but do nothing in this implementation. They may disappear in future releases, and issue a warning to that effect. I'm glad openssl can be built with System V m4..