disable fetching gtest, use the ports one

Index: tests/CMakeLists.txt
--- tests/CMakeLists.txt.orig
+++ tests/CMakeLists.txt
@@ -2,28 +2,10 @@
 
 project(${CMAKE_PROJECT_NAME}Tests CXX)
 
-# Set up GoogleTest
-include(FetchContent)
-
-FetchContent_Declare(
-  googletest
-  GIT_REPOSITORY https://github.com/google/googletest.git
-  GIT_TAG v1.15.2
-)
-
-# For Windows: Prevent overriding the parent project's compiler/linker settings
-set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
-
-# Disable building GMock
-set(BUILD_GMOCK OFF CACHE BOOL "" FORCE)
-
-# Do not install GTest 
-set(INSTALL_GTEST OFF CACHE BOOL "" FORCE)
-
-FetchContent_MakeAvailable(googletest)
-
 foreach(executable dbf_test sbn_test shp_test)
   add_executable(${executable} ${PROJECT_SOURCE_DIR}/${executable}.cc)
+  target_include_directories(${executable} PRIVATE /usr/local/include)
+  target_link_directories(${executable} PRIVATE /usr/local/lib)
   target_link_libraries(${executable} PRIVATE ${PACKAGE} gtest)
   add_test(
     NAME ${executable}
