use Benchmark;

timethese( 1000, {
 open => sub {
     open my $handle, $^X.' -V:ccflags |';
     my $ccflags = <$handle>;
     delete $INC{'Config.pm'};
 },
 use => sub {
     require Config; Config->import;
     my $ccflags = $Config{ccflags};
     delete $INC{'Config.pm'};
 },
} );