Update user dir config file search path

Search in XDG_CONFIG_HOME as per XDG Base Directory Specification
in addition to $HOME/.openocd.

On Darwin, search in ~/Library/Preferences/org.openocd/ which
appears to be one of the conventional locations.

Make $OPENOCD_SCRIPTS highest priority on all platforms, previously
it was only higher on WIN32.

Update the documentation to reflect the search order.

Change-Id: Ibaf4b59b51fdf452712d91b47ea2b5312bb5ada9
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/3890
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

doc/openocd.texi

@@ -724,8 +724,11 @@ Configuration files and scripts are searched for in
 @item the current directory,
 @item any search dir specified on the command line using the @option{-s} option,
 @item any search dir specified using the @command{add_script_search_dir} command,
-@item @file{$HOME/.openocd} (not on Windows),
 @item a directory in the @env{OPENOCD_SCRIPTS} environment variable (if set),
+@item @file{%APPDATA%/OpenOCD} (only on Windows),
+@item @file{$HOME/Library/Preferences/org.openocd} (only on Darwin),
+@item @file{$XDG_CONFIG_HOME/openocd} (@env{$XDG_CONFIG_HOME} defaults to @file{$HOME/.config}),
+@item @file{$HOME/.openocd},
 @item the site wide script library @file{$pkgdatadir/site} and
 @item the OpenOCD-supplied script library @file{$pkgdatadir/scripts}.
 @end enumerate

src/helper/options.c

@@ -178,6 +178,63 @@ static char *find_relative_path(const char *from, const char *to)
 	return relpath;
 }
 
+static void add_user_dirs(void)
+{
+	char *path;
+
+#if IS_WIN32
+	const char *appdata = getenv("APPDATA");
+
+	if (appdata) {
+		path = alloc_printf("%s/OpenOCD", appdata);
+		if (path) {
+			/* Convert path separators to UNIX style, should work on Windows also. */
+			for (char *p = path; *p; p++) {
+				if (*p == '\\')
+					*p = '/';
+			}
+			add_script_search_dir(path);
+			free(path);
+		}
+	}
+	/* WIN32 may also have HOME defined, particularly under Cygwin, so add those paths below too */
+#endif
+
+	const char *home = getenv("HOME");
+#if IS_DARWIN
+	if (home) {
+		path = alloc_printf("%s/Library/Preferences/org.openocd", home);
+		if (path) {
+			add_script_search_dir(path);
+			free(path);
+		}
+	}
+#endif
+	const char *xdg_config = getenv("XDG_CONFIG_HOME");
+
+	if (xdg_config) {
+		path = alloc_printf("%s/openocd", xdg_config);
+		if (path) {
+			add_script_search_dir(path);
+			free(path);
+		}
+	} else if (home) {
+		path = alloc_printf("%s/.config/openocd", home);
+		if (path) {
+			add_script_search_dir(path);
+			free(path);
+		}
+	}
+
+	if (home) {
+		path = alloc_printf("%s/.openocd", home);
+		if (path) {
+			add_script_search_dir(path);
+			free(path);
+		}
+	}
+}
+
 static void add_default_dirs(void)
 {
 	char *path;
@@ -194,32 +251,11 @@ static void add_default_dirs(void)
 	 * listed last in the built-in search order, so the user can
 	 * override these scripts with site-specific customizations.
 	 */
-	const char *home = getenv("HOME");
-
-	if (home) {
-		path = alloc_printf("%s/.openocd", home);
-		if (path) {
-			add_script_search_dir(path);
-			free(path);
-		}
-	}
-
 	path = getenv("OPENOCD_SCRIPTS");
-
 	if (path)
 		add_script_search_dir(path);
 
-#ifdef _WIN32
+	add_user_dirs();
-	const char *appdata = getenv("APPDATA");
-
-	if (appdata) {
-		path = alloc_printf("%s/OpenOCD", appdata);
-		if (path) {
-			add_script_search_dir(path);
-			free(path);
-		}
-	}
-#endif
 
 	path = alloc_printf("%s/%s/%s", exepath, bin2data, "site");
 	if (path) {