Added limited support for Method::Signatures to Perl parser

Hi,

Could you please accept my change - I added support for Method::Signatures into a perl parser. Now they recognize functions definition in 3 forms:
Standard: 
```
sub function {
 my @args = @_;
 ... logic here
}
```

Introduced by the package:
```
func function ( $var1, $var2, $var3 ) {
... login here
}
```

```
method function ( $var1, $var2, $var3 ) {
... logic here
}
```

method is a keyword for class methods.

There is also a minor fix in build.sh: it fails to build because for some reason there was no a reference to pcre.h and clang died on that.

Thanks,
Dmitry