Replace most uses of Boost.{Filesystem,Process}

With the `ghc::filesystem` dependency from the previous commit. If we
can replace the rest of the Boost.Filesystem dependency then we can get
rid the one nasty runtime dependency we have, and it will make
implementing the chainloading simpler since can reuse more code without
bringing in Boost.

src/plugin/utils.h

@@ -34,7 +34,7 @@ struct DefaultWinePrefix {};
  * environment variable.
  */
 struct OverridenWinePrefix {
-    boost::filesystem::path value;
+    ghc::filesystem::path value;
 };
 
 /**
@@ -81,7 +81,7 @@ struct PluginInfo {
      * Return the path to the actual Wine prefix in use, taking into account
      * `WINEPREFIX` overrides and the default `~/.wine` fallback.
      */
-    boost::filesystem::path normalize_wine_prefix() const;
+    ghc::filesystem::path normalize_wine_prefix() const;
 
     /**
      * Return the installed Wine version. This is obtained by from `wine
@@ -103,7 +103,7 @@ struct PluginInfo {
      * module (since that has to be bundle on Linux) but rather the .so file
      * contained in that bundle.
      */
-    const boost::filesystem::path native_library_path_;
+    const ghc::filesystem::path native_library_path_;
 
    private:
     /**
@@ -113,7 +113,7 @@ struct PluginInfo {
      * instead. We store this intermediate value so we can determine the
      * plugin's architecture.
      */
-    const boost::filesystem::path windows_library_path_;
+    const ghc::filesystem::path windows_library_path_;
 
    public:
     const LibArchitecture plugin_arch_;
@@ -132,7 +132,7 @@ struct PluginInfo {
      *
      * https://developer.steinberg.help/pages/viewpage.action?pageId=9798275
      */
-    const boost::filesystem::path windows_plugin_path_;
+    const ghc::filesystem::path windows_plugin_path_;
 
     /**
      * The Wine prefix to use for hosting `windows_plugin_path_`. If the
@@ -144,7 +144,7 @@ struct PluginInfo {
      * prefix will be used instead.
      */
     const std::
-        variant<OverridenWinePrefix, boost::filesystem::path, DefaultWinePrefix>
+        variant<OverridenWinePrefix, ghc::filesystem::path, DefaultWinePrefix>
             wine_prefix_;
 };
 
@@ -174,7 +174,7 @@ std::string join_quoted_strings(std::vector<std::string>& strings);
  * @return A prefix string for log messages.
  */
 std::string create_logger_prefix(
-    const boost::filesystem::path& endpoint_base_dir);
+    const ghc::filesystem::path& endpoint_base_dir);
 
 /**
  * Finds the Wine VST host (either `yabridge-host.exe` or `yabridge-host.exe`
@@ -197,8 +197,8 @@ std::string create_logger_prefix(
  * @return The a path to the VST host, if found.
  * @throw std::runtime_error If the Wine VST host could not be found.
  */
-boost::filesystem::path find_vst_host(
-    const boost::filesystem::path& this_plugin_path,
+ghc::filesystem::path find_vst_host(
+    const ghc::filesystem::path& this_plugin_path,
     LibArchitecture plugin_arch,
     bool use_plugin_groups);
 
@@ -220,9 +220,9 @@ boost::filesystem::path find_vst_host(
  * @return A socket endpoint path that corresponds to the format described
  *   above.
  */
-boost::filesystem::path generate_group_endpoint(
+ghc::filesystem::path generate_group_endpoint(
     const std::string& group_name,
-    const boost::filesystem::path& wine_prefix,
+    const ghc::filesystem::path& wine_prefix,
     const LibArchitecture architecture);
 
 /**
@@ -233,6 +233,8 @@ boost::filesystem::path generate_group_endpoint(
  * environment variable can be a big hurdle if you've never done anything like
  * that before. And since this is the recommended installation location, it
  * makes sense to also search there by default.
+ *
+ * FIXME: Replace Boost.Filesystem
  */
 std::vector<boost::filesystem::path> get_augmented_search_path();
 
@@ -240,7 +242,7 @@ std::vector<boost::filesystem::path> get_augmented_search_path();
  * Return a path to this `.so` file. This can be used to find out from where
  * this link to or copy of `libyabridge-{vst2,vst3}.so` was loaded.
  */
-boost::filesystem::path get_this_file_location();
+ghc::filesystem::path get_this_file_location();
 
 /**
  * Load the configuration that belongs to a copy of or symlink to
@@ -263,7 +265,7 @@ boost::filesystem::path get_this_file_location();
  *
  * @see Configuration
  */
-Configuration load_config_for(const boost::filesystem::path& yabridge_path);
+Configuration load_config_for(const ghc::filesystem::path& yabridge_path);
 
 /**
  * Send a desktop notification using `notify-send`. Used for diagnostics when a
@@ -299,14 +301,14 @@ bool send_notification(const std::string& title,
  * @return The path to the *file* found, or `std::nullopt` if the file could not
  *   be found.
  */
-template <invocable_returning<bool, const boost::filesystem::path&> F =
-              bool(const boost::filesystem::path&)>
-std::optional<boost::filesystem::path> find_dominating_file(
+template <invocable_returning<bool, const ghc::filesystem::path&> F =
+              bool(const ghc::filesystem::path&)>
+std::optional<ghc::filesystem::path> find_dominating_file(
     const std::string& filename,
-    boost::filesystem::path starting_dir,
-    F&& predicate = boost::filesystem::exists) {
+    ghc::filesystem::path starting_dir,
+    F&& predicate = ghc::filesystem::exists) {
     while (starting_dir != "") {
-        const boost::filesystem::path candidate = starting_dir / filename;
+        const ghc::filesystem::path candidate = starting_dir / filename;
         if (predicate(candidate)) {
             return candidate;
         }