[Chapel Merge] Fix #18050: Ensure GASNet can use hwloc

Branch: refs/heads/main
Revision: 88f00b850c09e8116ac559190a496a0d58a34a5f
Author: bonachea
Link: Fix #18050: Ensure GASNet can use hwloc by bonachea · Pull Request #25206 · chapel-lang/chapel · GitHub
Log Message:
Fix #18050: Ensure GASNet can use hwloc (#25206)

PR #18049 temporarily disabled GASNet's use of hwloc to work-around link
failures arising from disparate versions of hwloc ending up in the same
executable. Unfortunately this also hobbled GASNet's built-in support
for toplogy-aware intelligent selection of network adapter on multi-NIC
nodes, especially on InfiniBand multi-rail systems.

This commit restores GASNet's ability to detect hwloc, and ensures that
it uses the same hwloc as the rest of the Chapel runtime.

I've tested this on the JLSE Cascade InfiniBand cluster using both
CHPL_HWLOC=bundled and CHPL_HWLOC=system

[Contributed by @bonachea, reviewed and merged by @jabraham17]

Compare: Comparing 00d7194f0da7ef88ee0a3da0c2166a12d5a159aa...38ebc4340d1ac8dcf7360c5f3e65be778b1c25c7 · chapel-lang/chapel · GitHub

Diff:
M third-party/gasnet/Makefile
https://github.com/chapel-lang/chapel/pull/25206.diff