Rollup merge of #44372 - bgermann:master, r=alexcrichton
Rollup merge of #44372 - bgermann:master, r=alexcrichton

Use memalign instead of posix_memalign for Solaris

As pointed out in https://github.com/rust-lang/libc/commit/deb61c8,
Solaris 10 does not support posix_memalign.
Use memalign for all Solaris versions instead.
With this change applied I am able to cross-build rustc for Solaris 10.

GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,aidancully/rust