make internal declarations for flockfile tracking functions checkable

logically these belong to the intersection of the stdio and pthread
subsystems, and either place the declarations could go (stdio_impl.h
or pthread_impl.h) requires a forward declaration for one of the
argument types.

src/internal/stdio_impl.h

@@ -80,6 +80,11 @@ FILE *__ofl_add(FILE *f);
 FILE **__ofl_lock(void);
 void __ofl_unlock(void);
 
+struct __pthread;
+void __register_locked_file(FILE *, struct __pthread *);
+void __unlist_locked_file(FILE *);
+void __do_orphaned_stdio_locks(void);
+
 #define feof(f) ((f)->flags & F_EOF)
 #define ferror(f) ((f)->flags & F_ERR)
 

src/stdio/flockfile.c

@@ -1,8 +1,6 @@
 #include "stdio_impl.h"
 #include "pthread_impl.h"
 
-void __register_locked_file(FILE *, pthread_t);
-
 void flockfile(FILE *f)
 {
 	if (!ftrylockfile(f)) return;

src/stdio/funlockfile.c

@@ -1,8 +1,6 @@
 #include "stdio_impl.h"
 #include "pthread_impl.h"
 
-void __unlist_locked_file(FILE *);
-
 void funlockfile(FILE *f)
 {
 	if (f->lockcount == 1) {