Suppress build warning from test script

Author: Blake-Madden

tests/CMakeLists.txt

@@ -106,7 +106,7 @@ if(TE_BUILD_TEST_RUNNER)
     endif()
     if (CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
         set_source_files_properties(
-            tinyexpr.cpp PROPERTIES COMPILE_FLAGS "-Werror=unused-function")
+            tinyexpr.cpp PROPERTIES COMPILE_FLAGS "-Wno-unused-function")
     endif()
     if(MSVC)
         target_compile_definitions(${CMAKE_PROJECT_NAME} PUBLIC _DISABLE_VECTOR_ANNOTATION _DISABLE_STRING_ANNOTATION