Try fixing MSVC error.

Author: breyerml

tests/CMakeLists.txt

@@ -7,8 +7,8 @@
 list(APPEND CMAKE_MESSAGE_INDENT "Tests:  ")
 
 # setup testing wit GoogleTest
-set(PLSSVM_googletest_VERSION v1.14.0)
-find_package(GTest 1.14.0 QUIET)
+set(PLSSVM_googletest_VERSION v1.15.2)
+find_package(GTest 1.15.2 QUIET)
 if (GTEST_FOUND)
     message(STATUS "Found package GTest.")
 else ()
@@ -34,6 +34,12 @@ else ()
     set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
     FetchContent_MakeAvailable(googletest)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_OLD}")
+    
+    # try fixing MSVC Windows problem
+    if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+        message(STATUS "Change GTEST_API_ in the gtest_main.cc file.")
+        set_source_files_properties("${googletest_SOURCE_DIR}/src/gtest_main.cc" PROPERTIES COMPILE_DEFINITIONS GTEST_API_="")
+    endif ()
 endif ()
 
 # create larger test files if desired