[flang] Temp Driver - pass the flag to change the default integer kind through to F18_FC

fixes BUG 46307

Differential Revision: https://reviews.llvm.org/D84266

Author: AlexisPerry

flang/tools/f18/f18.cpp

@@ -545,6 +545,11 @@ int main(int argc, char *const argv[]) {
       defaultKinds.set_defaultIntegerKind(8);
       defaultKinds.set_subscriptIntegerKind(8);
       defaultKinds.set_sizeIntegerKind(8);
+      if (isPGF90) {
+        driver.F18_FCArgs.push_back("-i8");
+      } else {
+        driver.F18_FCArgs.push_back("-fdefault-integer-8");
+      }
     } else if (arg == "-Mlargearray") {
     } else if (arg == "-Mnolargearray") {
     } else if (arg == "-flarge-sizes") {