#33 Patch for compilation under OS X

[iMichka]

Hi. I am one of the homebrew-science maintainers. We just rebuilt maq for our users and there were a bunch of compilation errors with clang/llvm, and newer gcc versions.
Here are the errors:

In file included from mapcheck.cc:11:
./stdhash.hh:415:13: error: use of undeclared identifier 'directinsertaux'
                int ret = directinsertaux(key, this->ncapacity, this->keys, this->flags, &i);
                          ^
                          this->
mapcheck.cc:24:10: note: in instantiation of member function 'hashsetmisc<unsigned long long>::insert' requested here
                        hash->insert((bit64t)seqid<<32 | (pos-1));
                              ^
./stdhash.hh:295:13: note: must qualify identifier to find this declaration in dependent base class
        inline int directinsertaux(const keytypet &key, hashintt m, keytypet K, lh3flagt F, hashintt i) {
                   ^
1 error generated.

We came up with a small patch, that you may consider including in the next release. I am attaching the patch to this discussion. Here is the relevant discussion.