Added pthread package search

Utilities/CMake/FindDCMTK.cmake

@@ -124,6 +124,15 @@ foreach(lib
   
 endforeach()
 
+set(CMAKE_THREAD_LIBS_INIT)
+if( DCMTK_oflog_LIBRARY_RELEASE OR DCMTK_oflog_LIBRARY_DEBUG )
+  # Hack - Not having a DCMTKConfig.cmake file to read the settings from, we will attempt to
+  # find the library in all cases.
+  # Ideally, pthread library should be discovered only if DCMTK_WITH_THREADS is enabled.
+  set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
+  find_package(Threads)
+endif()
+
 set(DCMTK_config_TEST_HEADER osconfig.h)
 set(DCMTK_dcmdata_TEST_HEADER dctypes.h)
 set(DCMTK_dcmimage_TEST_HEADER dicoimg.h)