Adding the function have_smithlab_cpp for checking if smithlab_cpp is available as a library

Author: andrewdavidsmith

smithlab_utils.cpp

@@ -28,6 +28,8 @@
 using std::vector;
 using std::string;
 
+char have_smithlab_cpp() {return 1;}
+
 /* Performs Hochberg step-up p-value adjustment.
  */
 void smithlab::correct_pvals(const size_t n_tests, vector<double> &pvals ) {

smithlab_utils.hpp

@@ -37,6 +37,7 @@
 #include <numeric>
 #include <iomanip>
 
+extern "C" {char have_smithlab_cpp();}
 
 namespace smithlab {
   template <class In, class Out, class Pred> Out