* Makefile.in (DLL_OFILES): Add hookapi.o. Eliminate some cruft.

* cygheap.h (cygheap_types): Add new enum: HEAP_1_HOOK.
(hook_chain): New struct.
(init_cygheap::hooks): Define new element.
* cygheap.cc (cygheap_fixup_in_child): Zero hook chain on exec.
* dcrt0.cc (dll_crt0_1): Call ld_preload just before calling main function.
* external.cc (cygwin_internal): Implement CW_HOOK.
* fork.cc (fork_child): Call fixup_hooks_after_fork.
* init.cc (cygwin_hmodule): Reinstate after a long absence.
* include/sys/cygwin.h: Define CW_HOOK.
* hookapi.cc: New file.
* select.cc (start_thread_socket): Add debugging output.
* fhandler_disk_file.cc (fhandler_disk_file::fchmod): gcc 4.x accommodation.
* fhandler_socket.cc (fhandler_socket::connect): Make sure that err is
initialized.

winsup/cygwin/include/sys/cygwin.h

@@ -49,6 +49,7 @@ struct __cygwin_perfile
 
 /* External interface stuff */
 
+/* Always add at the bottom.  Do not add new values in the middle. */
 typedef enum
   {
     CW_LOCK_PINFO,
@@ -78,7 +79,8 @@ typedef enum
     CW_GET_SHMLBA,
     CW_GET_UID_FROM_SID,
     CW_GET_GID_FROM_SID,
-    CW_GET_BINMODE
+    CW_GET_BINMODE,
+    CW_HOOK
   } cygwin_getinfo_types;
 
 #define CW_NEXTPID	0x80000000	/* or with pid to get next one */