Enhance code to solve unresolved symbols of windows. Do not export mt, but use it internally.

Author: pradal

src/cpp/stat_tool/distribution.cpp

@@ -596,6 +596,11 @@ void set_seed(int seed, std::mt19937 &generator)
 	generator.seed(seed);
 }
 
+STAT_TOOL_API void set_seed(int seed)
+{
+  set_seed(seed, mt);
+}
+
 /*--------------------------------------------------------------*/
 /**
  *  \brief Computation of the column width for an integer value.

src/cpp/stat_tool/stat_tools.h

@@ -1037,7 +1037,8 @@ namespace stat_tool {
   STAT_TOOL_API extern std::mt19937 mt;
   STAT_TOOL_API extern std::uniform_real_distribution<double> rand_unif;
 
-  STAT_TOOL_API void set_seed(int seed, std::mt19937 &generator=mt);
+  STAT_TOOL_API void set_seed(int seed, std::mt19937 &generator);
+  STAT_TOOL_API void set_seed(int seed);
 
   STAT_TOOL_API int column_width(int);
   STAT_TOOL_API int column_width(int min_value , int max_value);