https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113143
--- Comment #10 from Ian Lance Taylor <ian at airs dot com> --- The makecontext/getcontext/setcontext functions are called by libgo on GNU/Linux for all targets other than x86_64. It is not the case that they are used only on *BSD systems. The default gc implementation does not require these functions because it provides assembler code. This of course limits the gc implementation to only support a limited number of targets: those for which the assembler code exists. libgo is intended to be more portable. To be clear I am fine with removing or guarding references to ucontext.h where that makes sense. I'm just pointing out that the code can't in general work if the *context functions are not available. It's unfortunate that POSIX removed them without providing adequate replacements. Saying that they "can be replaced using POSIX threads functions" is simply false. They provide a portable mechanism for a userspace threads mechanism on top of POSIX threads. Without them there is no way for libgo to implement goroutines efficiently.
