IBM i defines both of the __PASE__ and _AIX macros.
Commit 693b534 includes the wrong header file.
Need to check macro __PASE__ prior to _AIX.
PR-URL: https://github.com/libuv/libuv/pull/2371
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>