Fix handling of query_driver option in config file (#243)

tests/test_config.cc

@@ -32,6 +32,7 @@ TEST_CASE("Test config simple", "[unit-test]")
 
     auto cfg = clanguml::config::load("./test_config_data/simple.yml");
 
+    CHECK(cfg.query_driver() == "g++");
     CHECK(cfg.diagrams.size() == 1);
     auto &diagram = *cfg.diagrams["class_main"];
     CHECK(diagram.type() == clanguml::common::model::diagram_t::kClass);

tests/test_config_data/complete.yml

@@ -2,6 +2,8 @@
 compilation_database_dir: debug
 # The directory where *.puml files will be generated
 output_directory: docs/diagrams
+# Query compiler frontend for compilation flags
+query_driver: .
 # Set this as default for all diagrams
 generate_method_arguments: none
 # Enable generation of hyperlinks to diagram elements

tests/test_config_data/simple.yml

@@ -1,6 +1,7 @@
 compilation_database_dir: debug
 comment_parser: clang
 output_directory: output
+query_driver: g++
 generate_template_argument_dependencies: false
 diagrams:
   class_main: