The section on architecture support of dietlibc is too optimistic, IMHO. I stumbled upon quite a few function, esp. floating-point-related functions, that simply aren't implemented on x86_64 while they're available while they're available on x86.
But then one needs to understand the background of how and why dietlibc came to be: its original author used to work for a German company developing digital TV set-top boxes and receivers, based on Linux and technologies like DirectFB, so obviously supporting their requirements and optimizing for size aggressively, even if some functionality is non-conformant, has always been a priority.
Full disclosure: I contributed a few patches to dietlibc.
But then one needs to understand the background of how and why dietlibc came to be: its original author used to work for a German company developing digital TV set-top boxes and receivers, based on Linux and technologies like DirectFB, so obviously supporting their requirements and optimizing for size aggressively, even if some functionality is non-conformant, has always been a priority.
Full disclosure: I contributed a few patches to dietlibc.