Make builds verbose on master branch.

This is to allow comparison of the build instructions generated
on appveyor for mingw and cygwin with those for our
experiments with these platforms on GitHub Actions.

CMakeLists.txt

@@ -19,7 +19,7 @@ useCompilerCache()
 
 add_subdirectory(ApprovalTests)
 
-set(CMAKE_VERBOSE_MAKEFILE off)
+set(CMAKE_VERBOSE_MAKEFILE on)
 
 if (APPROVAL_TESTS_ENABLE_CODE_COVERAGE)
     include(CodeCoverage)