refactor: test for intel oneapi env vars (#125)

pymake/pymake_base.py

@@ -1165,9 +1165,11 @@ def _create_win_batch(
     # open the batch file
     f = open(batchfile, "w")
 
-    # write the compilervars batch command to batchfile
-    line = "call " + intel_setvars + "\n"
-    f.write(line)
+    # only write the compilervars batch command to batchfile if env vars aren't already configured
+    # https://www.intel.com/content/www/us/en/develop/documentation/oneapi-programming-guide/top/oneapi-development-environment-setup/use-the-setvars-script-with-windows.html
+    if os.environ.get("SETVARS_COMPLETED") != "1":
+        line = "call " + intel_setvars + "\n"
+        f.write(line)
 
     # assume that header files may be in other folders, so make a list
     searchdir = []