* 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/cygheap.cc

@@ -21,7 +21,6 @@
 #include "child_info.h"
 #include "heap.h"
 #include "sync.h"
-#include "shared_info.h"
 #include "sigproc.h"
 
 init_cygheap NO_COPY *cygheap;
@@ -185,6 +184,7 @@ cygheap_fixup_in_child (bool execed)
 
   if (execed)
     {
+      cygheap->hooks.next = NULL;
       cygheap->user_heap.base = NULL;		/* We can allocate the heap anywhere */
       /* Walk the allocated memory chain looking for orphaned memory from
 	 previous execs */