[llvm] [flang-rt] Add the ability to have user supplied callback functions to further customize the runtime environment. (PR #155646)

[Peter Klausler via llvm-commits]

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@@ -173,6 +182,14 @@ void ExecutionEnvironment::Configure(int ac, const char *av[],
   }
 
   // TODO: Set RP/ROUND='PROCESSOR_DEFINED' from environment
+
+  if (0 != nPostConfigEnvCallback) {
+    // Run an optional callback function in reverse order of registration
+    // after the core of the ExecutionEnvironment() logic.
+    for (auto i = 0; i != nPostConfigEnvCallback; ++i) {
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klausler wrote:

`int i{0};`

https://github.com/llvm/llvm-project/pull/155646