* fork.cc (vfork): Store complete stack frame in vfork_save structure for later

recovery.
* spawn.cc (spawn_guts): Reorganize slightly to consolidate handling when there
is a CreateProcess error.
(_spawnve): Only longjmp back to vfork handling when a process has been
successfuly started.
* winsup.h (vfork_save): Extend to include frame info.  Remove obsolete cpplus
conditionals.

winsup/cygwin/winsup.h

@@ -224,9 +224,9 @@ struct vfork_save
 {
   int pid;
   jmp_buf j;
+  DWORD frame[100];
   char **vfork_ebp;
-  char *caller_ebp;
-  char *retaddr;
+  char **vfork_esp;
   int is_active () { return pid < 0; }
 };
 
@@ -460,9 +460,6 @@ extern void (*__DTOR_LIST__) (void);
 /* Initial and increment values for cygwin's fd table */
 #define NOFILE_INCR    32
 
-#ifdef __cplusplus
-extern "C" {
-#endif
 #include <sys/reent.h>
 
 #define STD_RBITS (S_IRUSR | S_IRGRP | S_IROTH)
@@ -472,10 +469,6 @@ extern "C" {
 #define O_NOSYMLINK 0x080000
 #define O_DIROPEN   0x100000
 
-#ifdef __cplusplus
-}
-#endif
-
 /*************************** Environment ******************************/
 
 /* The structure below is used to control conversion to/from posix-style