ENH: Use GTest::gtest and GTest::gtest_main targets

These are the targets currently exported by CMake's FindGTest.

Remove the GTest::GTest, and GTest::Main targets which depricated in
CMake 3.20, and removed in CMake 4.1.0.

Author: blowekamp

CMake/ITKModuleTest.cmake

@@ -278,8 +278,8 @@ function(CreateGoogleTestDriver KIT KIT_LIBS KitTests)
   target_link_libraries(
     ${exe}
     ${KIT_LIBS}
-    GTest::GTest
-    GTest::Main
+    GTest::gtest
+    GTest::gtest_main
   )
   target_link_options(
     ${exe}

Modules/ThirdParty/GoogleTest/CMakeLists.txt

@@ -4,7 +4,7 @@ set(ITKGoogleTest_THIRD_PARTY 1)
 if(ITK_USE_SYSTEM_GOOGLETEST)
   if( NOT DEFINED GTEST_ROOT OR NOT EXISTS "${GTEST_ROOT}/CMakeLists.txt")
     set(ITKGoogleTest_NO_SRC 1)
-    set(ITKGoogleTest_LIBRARIES GTest::GTest GTest::Main)
+    set(ITKGoogleTest_LIBRARIES GTest::gtest GTest::gtest_main)
     set(ITKGoogleTest_EXPORT_CODE_BUILD "
 if(NOT ITK_BINARY_DIR)
   set(GTEST_ROOT \"${GTEST_ROOT}\")

Modules/ThirdParty/GoogleTest/src/CMakeLists.txt

@@ -29,15 +29,8 @@ endif()
 add_subdirectory( "${GTEST_SRC}"
   "${CMAKE_CURRENT_BINARY_DIR}/GTest-build" EXCLUDE_FROM_ALL)
 
-
-# The standard CMake FindGTest exports namespace targets, create
-# similar name alias and export names
-
-add_library(GTest::GTest ALIAS gtest)
-add_library(GTest::Main ALIAS gtest_main)
-
-set_property(TARGET gtest PROPERTY EXPORT_NAME GTest::GTest)
-set_property(TARGET gtest_main PROPERTY EXPORT_NAME GTest::Main)
+set_property(TARGET gtest PROPERTY EXPORT_NAME GTest::gtest)
+set_property(TARGET gtest_main PROPERTY EXPORT_NAME GTest::gtest_main)
 
 itk_module_target(gtest NO_INSTALL)
 itk_module_target(gtest_main NO_INSTALL)