PATCH: zsh-3.1.5-pws-6: some basic cygwin path handling fixes

[Matt Armstrong <matt_armstrong@xxxxxxxxxxx>]

There are some problems with zsh's pathname handling that don't work
when cygwin's (poorly thought out) drive letter hacks are in effect:

1) "//<drive-letter>/dir" is a valid path.  builtin.c's fixdir()
   strips off double slashes, which breaks things.

2) If you chdir("..") while in //D you're put in "/" but "/D" is not a
   directory in "/".  This breaks zgetdir().  (there is actually
   another bug in cygwin that breaks zgetdir(), but that is a moot
   point after my fix)

The fixes:

For #1, I just allow a leading // under cygwin.

For #2, I just have zgetdir() call getcwd() under cygwin.  I
considered having zgetdir() use getcwd() for all systems that had it.
I know the Linux kernel now has a getcwd() syscall, which is
presumbably much faster than zgetdir().  But I backed down from this
for fear that all the magic going on in zgetdir() works around bugs in
some system's implementations of getcwd().

Index: zsh/ChangeLog
diff -c zsh/ChangeLog:1.1.1.1 zsh/ChangeLog:1.4
*** zsh/ChangeLog:1.1.1.1	Sat Jan 23 18:10:11 1999
--- zsh/ChangeLog	Sat Jan 30 14:06:22 1999
***************
*** 1,3 ****
--- 1,34 ----
+ 1999-01-22  Matt Armstrong  <matt_armstrong@bigfoot.com>
+ 
+ 	* Src/compat.c (zgetdir): Use cygwin's getcwd() to avoid problems
+ 	with cygwin drive letters.
+ 
+ 	* Src/builtin.c (fixdir): Allow leading // under cygwin.
+ 
  Thu Oct 29 21:51:10 1998  Andrew Main  <zefram@zsh.org>
  
  	* Config/version.mk: Version 3.1.5.
Index: zsh/Src/builtin.c
diff -c zsh/Src/builtin.c:1.1.1.3 zsh/Src/builtin.c:1.4
*** zsh/Src/builtin.c:1.1.1.3	Sat Jan 30 10:15:04 1999
--- zsh/Src/builtin.c	Sat Jan 30 10:30:07 1999
***************
*** 1036,1041 ****
--- 1036,1044 ----
  {
      char *dest = src;
      char *d0 = dest;
+ #ifdef __CYGWIN__
+     char *s0 = src;
+ #endif
  
  /*** if have RFS superroot directory ***/
  #ifdef HAVE_SUPERROOT
***************
*** 1052,1057 ****
--- 1055,1065 ----
      for (;;) {
  	/* compress multiple /es into single */
  	if (*src == '/') {
+ #ifdef __CYGWIN__
+ 	    /* allow leading // under cygwin */
+ 	    if (src == s0 && src[1] == '/')
+ 		*dest++ = *src++;
+ #endif
  	    *dest++ = *src++;
  	    while (*src == '/')
  		src++;
Index: zsh/Src/compat.c
diff -c zsh/Src/compat.c:1.1.1.1 zsh/Src/compat.c:1.2
*** zsh/Src/compat.c:1.1.1.1	Sat Jan 23 18:10:11 1999
--- zsh/Src/compat.c	Sat Jan 23 20:33:09 1999
***************
*** 111,122 ****
  {
      char nbuf[PATH_MAX+3];
      char *buf;
!     int bufsiz, pos, len;
      struct stat sbuf;
      struct dirent *de;
      DIR *dir;
!     ino_t ino, pino;
!     dev_t dev, pdev;
  
      buf = halloc(bufsiz = PATH_MAX);
      pos = bufsiz - 1;
--- 111,127 ----
  {
      char nbuf[PATH_MAX+3];
      char *buf;
!     int bufsiz, pos;
      struct stat sbuf;
+     ino_t pino;
+     dev_t pdev;
+ #ifndef __CYGWIN__
      struct dirent *de;
      DIR *dir;
!     dev_t dev;
!     ino_t ino;
!     int len;
! #endif
  
      buf = halloc(bufsiz = PATH_MAX);
      pos = bufsiz - 1;
***************
*** 137,142 ****
--- 142,148 ----
  #ifdef HAVE_FCHDIR
      else
  #endif
+ #ifndef __CYGWIN__
  	holdintr();
  
      for (;;) {
***************
*** 221,226 ****
--- 227,247 ----
      if (*buf)
  	zchdir(buf + pos + 1);
      noholdintr();
+ 
+ #else  /* __CYGWIN__ case */
+ 
+     if (!getcwd(buf, bufsiz)) {
+ 	if (d) {
+ 	    return NULL;
+ 	}
+     } else {
+ 	if (d) {
+ 	    return d->dirname = ztrdup(buf);
+ 	}
+ 	return buf;
+     }
+ #endif
+ 
      buf[0] = '.';
      buf[1] = '\0';
      return buf;