tree 6db50e7182a04a0563109bf4950755d26b29dc97
parent b13f0da153aa47fbf113c44e734be2be603870b6
author Edward Thomson <ethomson@github.com> 1487759659 +0000
committer Edward Thomson <ethomson@github.com> 1487762516 +0000

Provide error on gcc < 4.1 when THREADSAFE

Provide a descriptive error message when compiling THREADSAFE on gcc
versions < 4.1.  We require the atomic primitives (eg
`__sync_synchronize`) that were introduced in that version.

(Note, clang setes `__GNUC__` but appears to set its version > 4.1.)