Squash of thread-safe PR cleanup

- expand functions
- add comment
- rename functions
- fix locking issue in format and mount
- use global include
- fix ac6 linker issue
- use the global config file
- address review comments
- minor cleanup
- minor cleanup
- review comments

lfs_util.h

@@ -43,8 +43,9 @@ extern "C"
 {
 #endif
 
-#ifndef LFS_THREAD_SAFE
-#define LFS_THREAD_SAFE 0
+// Enables thread-safe wrappers using the lock/unlock callbacks in lfs_config
+#ifndef LFS_THREADSAFE
+#define LFS_THREADSAFE 0
 #endif
 
 // Macros, may be replaced by system specific wrappers. Arguments to these