[clang] [Clang][Driver] Add gcc-14, 15 and 16 toolset path on RHEL (PR #178459)

[Nikita Popov via cfe-commits]

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@@ -2298,6 +2298,9 @@ void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
       D.getVFS().exists("/opt/rh")) {
     // TODO: We may want to remove this, since the functionality
     //   can be achieved using config files.
+    Prefixes.push_back("/opt/rh/gcc-toolset-16/root/usr");
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nikic wrote:

@MaskRay RHEL already provides a clang config file for this. The changes here are for Clang builds that are not distributed by RHEL. We don't have any control over those.

I agree that we should give the dynamic probing another try. It seems like that should still be possible, the check just needs to be a bit different than originally implemented.

https://github.com/llvm/llvm-project/pull/178459