Support testing for both Cygwin and MSYS

MSYS implies and derives from Cygwin in CMake

Author: kmilos

tests/CMakeLists.txt

@@ -74,10 +74,10 @@ else()
       COMMAND ${CMAKE_COMMAND} -E copy "$<TARGET_FILE_DIR:ojph_compress>/ojph_compress.wasm" "./"
     )
   endif(EMSCRIPTEN)
-  if(MSYS)
+  if(CYGWIN)
     add_custom_command(TARGET test_executables POST_BUILD
-      COMMAND ${CMAKE_COMMAND} -E copy "../bin/msys-gtest.dll" "./"
-      COMMAND ${CMAKE_COMMAND} -E copy "../bin/msys-gtest_main.dll" "./"
+      COMMAND ${CMAKE_COMMAND} -E copy "../bin/${CMAKE_SHARED_LIBRARY_PREFIX}gtest.dll" "./"
+      COMMAND ${CMAKE_COMMAND} -E copy "../bin/${CMAKE_SHARED_LIBRARY_PREFIX}gtest_main.dll" "./"
     )
-  endif(MSYS)
+  endif()
 endif(MSVC)