The techniques that configure/autoconf use are runtime techniques, and hence useless to my goal of doing the configuration at compile time. :-)
Basically, I ended up using stuff like:
\n#if defined(MSC_VER)\n// windows stuff\n#elif defined(linux) || defined(__linux__)\n// linux stuff\n#elif defined(sun) || defined(__sun__)\n// solaris stuff\n#else\n#error Unknown or unsupported OS\n#endif\n
...is another man's run time. How about having the make file run a configuration procedure that generates a header file with the constants in it. Something with pipes or grep or awk or.... :-)