wsutil: Add get_docfile_path()

wsutil/filesystem.c

@@ -2129,6 +2129,28 @@ get_datafile_path(const char *filename)
     }
 }
 
+/*
+ * Construct the path name of a global documentation file, given the
+ * file name.
+ *
+ * The returned file name was g_malloc()'d so it must be g_free()d when the
+ * caller is done with it.
+ */
+char *
+get_docfile_path(const char *filename)
+{
+    if (running_in_build_directory_flag) {
+        /* We're running in the build directory and the requested file is a
+         * generated (or a test) file.  Return the file name in the build
+         * directory (not in the source/data directory).
+         * (Oh the things we do to keep the source directory pristine...)
+         */
+        return g_build_filename(get_progfile_dir(), filename, (char *)NULL);
+    } else {
+        return g_build_filename(get_doc_dir(), filename, (char *)NULL);
+    }
+}
+
 /*
  * Return an error message for UNIX-style errno indications on open or
  * create operations.

wsutil/filesystem.h

@@ -136,6 +136,15 @@ WS_DLL_PUBLIC const char *get_doc_dir(void);
  * The returned file name was g_malloc()'d so it must be g_free()d when the
  * caller is done with it.
  */
+WS_DLL_PUBLIC char *get_docfile_path(const char *filename);
+
+/*
+ * Construct the path URL of a global documentation file, given the
+ * file name.
+ *
+ * The returned file name was g_malloc()'d so it must be g_free()d when the
+ * caller is done with it.
+ */
 WS_DLL_PUBLIC char *doc_file_url(const char *filename);
 
 /*