changed git clone destination of C++GSL

to avoid conflicts with the other GSL (GNU Scientific Library)

CMakeLists.txt

@@ -14,14 +14,15 @@ if(NOT GAUDI_USE_SYSTEM_CPP_GSL)
   set(CPP_GSL_URL https://github.com/Microsoft/GSL)
   set(CPP_GSL_VERSION 32ca283d)
   message(STATUS "Using and shipping ${CPP_GSL_URL} version ${CPP_GSL_VERSION}")
-  if(NOT EXISTS ${CMAKE_CURRENT_BINARY_DIR}/GSL)
-    execute_process(COMMAND git clone ${CPP_GSL_URL})
+  set(CPP_GSL_DIR ${CMAKE_CURRENT_BINARY_DIR}/ext/GSL)
+  if(NOT EXISTS ${CPP_GSL_DIR})
+    execute_process(COMMAND git clone ${CPP_GSL_URL} ${CPP_GSL_DIR})
   endif()
   execute_process(COMMAND git checkout ${CPP_GSL_VERSION}
-                  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/GSL)
-  install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/GSL/gsl DESTINATION include)
-  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/GSL/LICENSE DESTINATION include/gsl/LICENSE)
-  set(CPP_GSL_INCLUDE_DIR NAMES ${CMAKE_CURRENT_BINARY_DIR}/GSL)
+                  WORKING_DIRECTORY ${CPP_GSL_DIR})
+  install(DIRECTORY ${CPP_GSL_DIR}/gsl DESTINATION include)
+  install(FILES ${CPP_GSL_DIR}/LICENSE DESTINATION include/gsl/LICENSE)
+  set(CPP_GSL_INCLUDE_DIR NAMES ${CPP_GSL_DIR})
 else()
   find_path(CPP_GSL_INCLUDE_DIR NAMES gsl/gsl)
 endif()