Logging: Add customizable logging backends and fmtlib based macros

* Change the logging backend to support multiple sinks through the
Backend Interface
* Add a new set of logging macros to use fmtlib instead.
* Qt: Compile as GUI application on windows to make the console hidden by
default. Add filter configuration and a button to open log location.
* SDL: Migrate to the new logging macros

src/common/string_util.h

@@ -134,4 +134,17 @@ bool ComparePartialString(InIt begin, InIt end, const char* other) {
  * NUL-terminated then the string ends at max_len characters.
  */
 std::string StringFromFixedZeroTerminatedBuffer(const char* buffer, size_t max_len);
-}
+
+/**
+ * Attempts to trim an arbitrary prefix from `path`, leaving only the part starting at `root`. It's
+ * intended to be used to strip a system-specific build directory from the `__FILE__` macro,
+ * leaving only the path relative to the sources root.
+ *
+ * @param path The input file path as a null-terminated string
+ * @param root The name of the root source directory as a null-terminated string. Path up to and
+ *             including the last occurrence of this name will be stripped
+ * @return A pointer to the same string passed as `path`, but starting at the trimmed portion
+ */
+const char* TrimSourcePath(const char* path, const char* root = "src");
+
+} // namespace Common