main: Fix two memory leaks

When Tesseract terminates by calling the exit function,
the destructor of any local auto variable is not called.

Fix two cases by using static variables.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

api/tesseractmain.cpp

@@ -424,7 +424,9 @@ int main(int argc, char** argv) {
   }
 
   PERF_COUNT_START("Tesseract:main")
-  tesseract::TessBaseAPI api;
+
+  // Avoid memory leak caused by auto variable when exit() is called.
+  static tesseract::TessBaseAPI api;
 
   api.SetOutputName(outputbase);
 
@@ -493,7 +495,8 @@ int main(int argc, char** argv) {
       (api.GetBoolVariable("tessedit_resegment_from_boxes", &b) && b) ||
       (api.GetBoolVariable("tessedit_make_boxes_from_boxes", &b) && b);
 
-  tesseract::PointerVector<tesseract::TessResultRenderer> renderers;
+  // Avoid memory leak caused by auto variable when exit() is called.
+  static tesseract::PointerVector<tesseract::TessResultRenderer> renderers;
 
   if (in_training_mode) {
     renderers.push_back(NULL);