Add support for changing the `diff` command via an environment variable

While the file arguments remain fixed the actual `diff` application and its output style can be changed using the `CHANGE_LOG_DIFF_CMD` environment variable.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/tracking/change_tracker.h b/src/tracking/change_tracker.h
index 54af4f7..24251e5 100644
--- a/src/tracking/change_tracker.h
+++ b/src/tracking/change_tracker.h
@@ -11,6 +11,7 @@ namespace tracking {
 
 class ChangeTracker {
 	public:
+		ChangeTracker(utility::Logger*, const std::string&);
 		ChangeTracker(utility::Logger*);
 		~ChangeTracker();
 
@@ -19,6 +20,7 @@ class ChangeTracker {
 		bool track(const std::string&);
 
 	private:
+		const std::string      diff_cmd_;
 		utility::Logger* const logger_;
 
 		std::unordered_map<