* 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/fhandler.h

@@ -149,13 +149,7 @@ public:
   void set_name (const char * unix_path, const char * win32_path = NULL,
 		 int unit = 0);
 
-  virtual fhandler_base& operator =(fhandler_base &x)
-  {
-    memcpy (this, &x, sizeof *this);
-    unix_path_name_ = x.unix_path_name_ ? strdup (x.unix_path_name_) : NULL;
-    win32_path_name_ = x.win32_path_name_ ? strdup (x.win32_path_name_) : NULL;
-    return *this;
-  };
+  virtual fhandler_base& operator =(fhandler_base &x);
   fhandler_base (DWORD dev, const char *name = 0, int unit = 0);
   virtual ~fhandler_base ();
 
@@ -243,7 +237,8 @@ public:
   unsigned long get_namehash () { return namehash_; }
 
   virtual void hclose (HANDLE h) {CloseHandle (h);}
-  virtual void set_inheritance (HANDLE &h, int not_inheriting, const char *name = NULL);
+  virtual void set_inheritance (HANDLE &h, int not_inheriting,
+				const char *name = NULL);
 
   /* fixup fd possibly non-inherited handles after fork */
   void fork_fixup (HANDLE parent, HANDLE &h, const char *name);
@@ -287,10 +282,7 @@ public:
   virtual int raw_read (void *ptr, size_t ulen);
   virtual int raw_write (const void *ptr, size_t ulen);
 
-  /* Function to save state of a fhandler_base into memory. */
-  virtual int linearize (unsigned char *);
-  /* Function to de-linearize into a fd */
-  virtual int de_linearize (const char *, const char *, const char *);
+  virtual void fixup_after_exec (HANDLE) {}
 
   /* Virtual accessor functions to hide the fact
      that some fd's have two handles. */
@@ -307,6 +299,12 @@ public:
     return windows_device_names[FHDEVN (status)];
   }
   virtual int bg_check (int) {return 1;}
+  void clear_readahead ()
+  {
+    raixput = raixget = ralen = rabuflen = 0;
+    rabuf = NULL;
+  }
+  void operator delete (void *);
 };
 
 class fhandler_socket: public fhandler_base
@@ -377,9 +375,6 @@ protected:
 public:
   ~fhandler_dev_raw (void);
 
-  /* Function to de-linearize into a fd */
-  int de_linearize (const char *, const char *, const char *);
-
   int open (const char *path, int flags, mode_t mode = 0);
   int close (void);
 
@@ -497,7 +492,7 @@ public:
   void dump ();
   int is_tty () { return 1; }
   void fixup_after_fork (HANDLE parent);
-  int de_linearize (const char *, const char *, const char *);
+  void fixup_after_exec (HANDLE);
 
   /* We maintain a pgrp so that tcsetpgrp and tcgetpgrp work, but we
      don't use it for permissions checking.  fhandler_tty_slave does
@@ -604,7 +599,7 @@ public:
   select_record *select_write (select_record *s);
   select_record *select_except (select_record *s);
   int ready_for_read (int fd, DWORD howlong, int ignra);
-  int de_linearize (const char *, const char *, const char *);
+  void fixup_after_exec (HANDLE);
   void set_close_on_exec (int val);
   void fixup_after_fork (HANDLE parent);
   void set_input_state ()
@@ -712,7 +707,7 @@ public:
   int init (int);
   int init_console ();
   void fixup_after_fork (HANDLE parent);
-  int de_linearize (const char *, const char *, const char *);
+  void fixup_after_exec (HANDLE);
 };
 
 class fhandler_dev_null: public fhandler_base