Import glob2regex

It's still missing ast optimization and some code cleanup is also
needed, but it should be working in the general case.
Also write a small unit test for it.

test/unit/CMakeLists.txt

@@ -3,6 +3,7 @@ project(${bare_name}-test CXX)
 add_executable(${PROJECT_NAME}
 	test_diriterator.cpp
 	test_guess_content_type.cpp
+	test_glob2regex.cpp
 )
 
 target_include_directories(${PROJECT_NAME} SYSTEM
@@ -15,6 +16,7 @@ target_link_libraries(${PROJECT_NAME}
 	PRIVATE ${bare_name}-machinery
 	PRIVATE gtest
 	PRIVATE gtest_main
+	PRIVATE glob2regex
 )
 
 add_test(