Here is a stab at switch the release script to build with cmake instead of autoconf. It retains an option to build with autoconf for platforms where that's necessary, such as Darwin.
Here is a diff between the resulting tarballs of building 3.6.1-rc1 on Linux with the old script vs. this new version:
.I removed the -build-triple option. That seems to be intended for cross-compiling and won't work with cmake. Does anyone know if that's actually used for any of our release binaries?
I'm also considering removing the "do_64bit" thing, as I'm not entirely sure how that's supposed to work. For me, it seems to always build two 64-bit packages. Let me know what you think.
(I will hold off committing this in any case until 3.6.2 is out the door to avoid that getting built with the wrong version script.)