* Makefile.in: Add cygheap.o.

* child_info.h: Add specific exec class.
* cygheap.h: New file.  Contains declarations for cygwin heap.
* cygheap.cc: New file.  Implements cygwin heap functions.
* dcrt0.cc (quoted): Simplify due to new method for passing arguments between
cygwin programs.
(alloc_stack_hard_way): Attempt to handle overlapped stack.
(dll_crt0_1): Move child_info processing here.  Accomodate new method for
passing arguments between cygwin programs.  Initialize cygwin heap.  Establish
__argc and __argv variables.
(_dll_crt0): Move most of child_info processing to dll_crt0_1.
(cygwin_dll_init): Remove duplication.
* dtable.cc (dtable::extend): Allocate dtable using cygwin heap.
(dtable::build_fhandler): Ditto for fhandler type being constructed.
(dtable::dup_worker): Free new fhandler from cygwin heap on error.
(dtable::select_*): Don't assume that this == fdtab.
(dtable::linearize_fd_array): Delete.
(dtable::delinearize_fd_array): Delete.
(dtable::fixup_after_exec): New file.
(dtable::vfork_child_dup): Use cygwin heap.
(dtable::vfork_parent_restore): Ditto.
* dtable.h: Remove obsolete methods.  Add new method.
* environ.cc (posify): Eliminate already_posix parameter and logic.
(envsize): New function.
(_addenv): Use envsize.
(environ_init): Accept an argument pointing to an existing environment list.
If supplied, allocate space for this in the the program's heap.
* fhandler.cc (fhandler_base::operator =): Move here from fhandler.h.  Use
cygwin heap to allocate filenames.
(fhandler_base::set_name): Allocate/free names from cygwin heap.
(fhandler_base::linearize): Delete.
(fhandler_base::de_linearize): Delete.
(fhandler_base::operator delete): Free from cygwin heap.
(fhandler_base::~fhandler_base): Ditto.
* fhandler.h: Accomodate elimination of *linearize and other changes above.
* fhandler_console.cc (fhandler_console::fixup_after_exec): Rename from
de_linearize.
* heap.h: New file.
* fhandler_tty.cc (fhandler_tty_slave::fhandler_tty_slave): Use cygwin heap for
name.  fhandler_tty::fixup_after_exec): Rename from de_linearize.
* fork.cc (fork): Call cygheap_fixup_in_child.
* heap.cc: Use declarations in heap.h.
* malloc.cc: Sprinkle assertions throughout to catch attempts to free/realloc
something from the cygwin heap.
* path.cc: Throughout, eliminate use of per-thread cache for cwd.  Use cwd_*
functions rather than cwd_* variables to access cwd_win32 and cwd_posix.
(cwd_win32): New function.
(cwd_posix): New function.
(cwd_hash): New function.
(cwd_fixup_after_exec): New function.
* path.h: Accomodate path.cc changes.
* pinfo.cc (pinfo_init): Accept a pointer to an environment table.  Pass this
to environ_init.  Eliminate old 'title' tests.
* pinfo.h: Accomodate above change in argument.
* spawn.cc (struct av): New method for building argv list.
(av::unshift): New method.
(spawn_guts): Allocate everything that the child process needs in the cygwin
heap and pass a pointer to this to the child.  Build argv list using new
method.  Eliminate delinearize stuff.
* thread.h: Eliminate _cwd_win32 and _cwd_posix buffers.
* winsup.h: Eliminate obsolete functions.  Add envsize() declaration.

winsup/cygwin/malloc_wrapper.cc

@@ -13,6 +13,9 @@ details. */
 
 #include "winsup.h"
 #include <stdlib.h>
+#include <assert.h>
+#include "cygheap.h"
+#include "heap.h"
 #include "sync.h"
 
 /* we provide these stubs to call into a user's
@@ -60,6 +63,8 @@ extern "C" void
 _free_r (struct _reent *, void *p)
 {
   export_malloc_called = 1;
+  assert (!incygheap (p));
+  assert (inheap (p));
   free (p);
 }
 #undef free
@@ -68,6 +73,8 @@ extern "C" void *
 _realloc_r (struct _reent *, void *p, size_t size)
 {
   export_malloc_called = 1;
+  assert (!incygheap (p));
+  assert (inheap (p));
   return realloc (p, size);
 }
 #undef realloc
@@ -122,6 +129,22 @@ calloc (size_t nmemb, size_t size)
   res = user_data->calloc (nmemb, size);
   return res;
 }
+
+extern "C" char *
+strdup (const char *s)
+{
+  char *p;
+  size_t len = strlen (s) + 1;
+  if ((p = (char *) malloc (len)) != NULL)
+      memcpy (p, s, len);
+  return p;
+}
+
+extern "C" char *
+_strdup_r (struct _reent *, const char *s)
+{
+  return strdup (s);
+}
 #endif
 
 /* These routines are used by the application if it
@@ -178,22 +201,6 @@ export_calloc (size_t nmemb, size_t size)
   return res;
 }
 
-extern "C" char *
-strdup (const char *s)
-{
-  char *p;
-  size_t len = strlen (s) + 1;
-  if ((p = (char *) malloc (len)) != NULL)
-      memcpy (p, s, len);
-  return p;
-}
-
-extern "C" char *
-_strdup_r (struct _reent *, const char *s)
-{
-  return strdup (s);
-}
-
 /* We use a critical section to lock access to the malloc data
    structures.  This permits malloc to be called from different
    threads.  Note that it does not make malloc reentrant, and it does