[flang] [llvm] [flang-rt] Runtime implementation of extended intrinsic function SECNDS() (PR #152021)

[Peter Klausler via llvm-commits]

================
@@ -309,6 +310,12 @@ std::int32_t RTNAME(Hostnm)(
   return status;
 }
 
+float RTNAME(Secnds)(float *refTime, const char *sourceFile, int line) {
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klausler wrote:

I was assuming that the other entry point was to handle calls that were to the non-intrinsic external name, as in 

```
      EXTERNAL SECNDS
      PRINT *, SECNDS(0.)
      END
```

https://github.com/llvm/llvm-project/pull/152021