libtcc: minor adjustments

- use {B} to substitute tcc_lih_path (instead of \b)

- expand CONFIG_TCC_CRTPREFIX in CONFIG_TCC_LIBPATHS
  which fixes duplicate CONFIG_SYSROOT.

- put default CONFIG_SYSROOT ("") into tcc.h

- remove hack from commit db6fcce78f
  because $(tccdir)/include is already in sysincludes

- configure: error out for unrecognized options.

- win32/build-tcc.bat: put libtcc into base dir where it will
  find lib/include automatically, and build libtcc_test example.

configure

@@ -168,6 +168,8 @@ for opt do
   ;;
   --help|-h) show_help="yes"
   ;;
+  *) echo "configure: unrecognized option $opt"; exit 1
+  ;;
   esac
 done
 
@@ -380,7 +382,7 @@ print_var2()
 {
   if test -n "$2"; then print_var1 $1 "$2"; fi
 }
-print_var1 CONFIG_SYSROOT "$sysroot"
+print_var2 CONFIG_SYSROOT "$sysroot"
 print_var1 CONFIG_TCCDIR "$tccdir"
 print_var2 CONFIG_TCC_SYSINCLUDEPATHS "$tcc_sysincludepaths"
 print_var2 CONFIG_TCC_LIBPATHS "$tcc_libpaths"