set PYTHONPATH to path of gmsh binary

Common/CommandLine.cpp

@@ -268,7 +268,6 @@ void GetOptions(int argc, char *argv[])
 
 #if defined(HAVE_PARSER)
   if(argc && argv){
-    CTX::instance()->argv0 = std::string(argv[0]);
     // parse session and option file (if argc/argv is not provided skip this
     // step: this is usually what is expected when using Gmsh as a library)
     ParseFile(CTX::instance()->homeDir + CTX::instance()->sessionFileName, true);

Common/Context.cpp

@@ -59,9 +59,7 @@ CTX::CTX() : gamepad(0)
   post.draw = 1;
   post.combineTime = 0; // try to combineTime views at startup
   lock = 0; // very primitive locking
-  ///
   fileread=false;
-  ///
 
 #if defined(HAVE_FLTK)
   glFontEnum = FL_HELVETICA;

Common/GmshMessage.cpp

@@ -17,6 +17,7 @@
 #include "Options.h"
 #include "Context.h"
 #include "OpenFile.h"
+#include "StringUtils.h"
 #include "OS.h"
 
 #if defined(HAVE_ONELAB)
@@ -112,6 +113,25 @@ void Msg::Init(int argc, char **argv)
     if(i) _commandLine += " ";
     _commandLine += argv[i];
   }
+
+  if(argc && argv){
+    CTX::instance()->argv0 = std::string(argv[0]);
+    std::vector<std::string> split = SplitFileName(CTX::instance()->argv0);
+
+    // add the directory where the binary is installed to the path where Python
+    // looks for modules
+    std::string path;
+    char *tmp = getenv("PYTHONPATH");
+    if(tmp){
+      path = tmp;
+      path += ":" + split[0];
+    }
+    else
+      path = split[0];
+    setenv("PYTHONPATH", path.c_str(), 1);
+    printf("pythonpath = %s\n", path.c_str());
+  }
+
   InitializeOnelab("Gmsh");
 }