Use global list[str] type for argv,

- Rename argv to _argv
- Initialize the argv values in C backend using `_lpython_set_argv` function call

src/libasr/codegen/asr_to_c.cpp

@@ -828,6 +828,7 @@ R"(
         }
         src = contains
                 + "int main(int argc, char* argv[])\n{\n"
+                + indent1 + "_lpython_set_argv(argc, argv);\n"
                 + decl + body
                 + indent1 + "return 0;\n}\n";
         indentation_level -= 2;

src/libasr/runtime/lfortran_intrinsics.c

@@ -1393,23 +1393,23 @@ LFORTRAN_API int32_t _lfortran_all(bool *mask, int32_t n) {
 }
 
 // Command line arguments
-int32_t argc;
-char **argv;
+int32_t _argc;
+char **_argv;
 
 LFORTRAN_API void _lpython_set_argv(int32_t argc_1, char *argv_1[]) {
-    argv = malloc(argc_1 * sizeof(char *));
+    _argv = malloc(argc_1 * sizeof(char *));
     for (size_t i = 0; i < argc_1; i++) {
-        argv[i] = strdup(argv_1[i]);
+        _argv[i] = strdup(argv_1[i]);
     }
-    argc = argc_1;
+    _argc = argc_1;
 }
 
 LFORTRAN_API int32_t _lpython_get_argc() {
-    return argc;
+    return _argc;
 }
 
 LFORTRAN_API char *_lpython_get_argv(int32_t index) {
-    return argv[index];
+    return _argv[index];
 }
 
 // << Command line arguments << ------------------------------------------------

src/runtime/sys.py

@@ -7,22 +7,26 @@ def exit(error_code: i32):
 
     quit(error_code)
 
+# >----------------------------------- argv ----------------------------------->
+@ccall
+def _lpython_get_argc() -> i32:
+    pass
+
+@ccall
+def _lpython_get_argv(index: i32) -> str:
+    pass
+
 def _lpython_argv() -> list[str]:
-    # TODO: use argv as a global `list[str]` variable
     """
     Gets the list of command line arguments
     """
     argc: i32 = _lpython_get_argc()
-    argv: list[str]
+    argv: list[str] = []
     i: i32
     for i in range(argc):
         argv.append(_lpython_get_argv(i))
     return argv
 
-@ccall
-def _lpython_get_argc() -> i32:
-    pass
+argv: list[str] = _lpython_argv()
 
-@ccall
-def _lpython_get_argv(index: i32) -> str:
-    pass
+# <----------------------------------- argv -----------------------------------<