[flang][driver] add option to make all main program variable static (#121968)

Co-authored-by: Kiran Chandramohan <kiranchandramohan@gmail.com>
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 7034e5b..75b10e8 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -57,7 +57,8 @@
                             options::OPT_fno_automatic,
                             options::OPT_fhermetic_module_files,
                             options::OPT_frealloc_lhs,
-                            options::OPT_fno_realloc_lhs});
+                            options::OPT_fno_realloc_lhs,
+                            options::OPT_fsave_main_program});
 }
 
 void Flang::addPreprocessingOptions(const ArgList &Args,