Switch to cmake + vcpkg, builds on linux, windows needs verification.

Code has been modified to be portable.

tests/mygtestutils/CMakeLists.txt

@@ -0,0 +1,19 @@
+add_library(mygtestutils STATIC
+    PrintTo_Qt.cpp
+    PrintTo_Qt.h
+    )
+
+target_link_libraries(mygtestutils PUBLIC
+    GTest::gtest
+    Qt6::Core
+    )
+
+target_include_directories(mygtestutils PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    )
+
+set_target_properties(mygtestutils PROPERTIES
+    CXX_STANDARD 20
+    CXX_STANDARD_REQUIRED ON
+    POSITION_INDEPENDENT_CODE ON
+    )