Hello,

As a feature, I suggest that musl supports the __STDC_WANT_LIB_EXT2__
feature test macro specified in the ISO/IEC Dynamic Allocations TR.
I've attached a patch to accomplish this and which makes minimal
changes to the headers to get musl's support comparable to glibc's.

I was not able to get my hands on the official publication, so I only
referred to the latest draft, which is available here:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1388.pdf

I'm not subscribed, so please CC me on replies.