8201226: missing JNIEXPORT / JNICALL at some places in function declarations/implementations

Co-authored-by: Alexey Ivanov <alexey.ivanov@oracle.com>
Reviewed-by: ihse, mdoerr

src/java.base/share/native/launcher/main.c

@@ -93,7 +93,7 @@ WinMain(HINSTANCE inst, HINSTANCE previnst, LPSTR cmdline, int cmdshow)
     __initenv = _environ;
 
 #else /* JAVAW */
-JNIEXPORT int JNICALL
+JNIEXPORT int
 main(int argc, char **argv)
 {
     int margc;