introduce test building cmake arg

CMakeLists.txt

@@ -12,6 +12,7 @@ set(CMAKE_C_STANDARD 23)
 
 OPTION(VANILLA_BUILD_DESKTOP "Build Qt app for Linux desktop" ON)
 OPTION(VANILLA_BUILD_RPI "Build SDL2 app for Raspberry Pi" OFF)
+OPTION(VANILLA_BUILD_TESTS "Build unit tests for Vanilla" OFF)
 
 add_subdirectory(lib)
 if (NOT ANDROID)

lib/CMakeLists.txt

@@ -21,9 +21,9 @@ endif()
 
 install(TARGETS vanilla)
 
-if (0)
+if (VANILLA_BUILD_TESTS)
     add_executable(bittest
-        bittest.c
+        tests/bittest.c
     )
 
     target_link_libraries(bittest PRIVATE vanilla m)