Patch #1197318: Cygwin case-sensitive import patch

A problem regarding importing symlinked modules was recently reported on the
Cygwin mailing list:

    http://cygwin.com/ml/cygwin/2005-04/msg00257.html

The following test case demonstrates the problem:

$ ls -l
total 1
lrwxrwxrwx    1 jt       None            6 Apr 23 13:32 bar.py -> foo.py
-rw-r--r--    1 jt       None           24 Apr 18 20:13 foo.py

$ python -c 'import bar'
Traceback (most recent call last):
File "<string>", line 1, in ?
ImportError: No module named bar

Since Cygwin's case_ok() uses a modified version of the Windows's version, the
symlinked bar module actually resolves to file foo.py instead of bar.py. This
obviously causes the matching code to fail (regardless of case).

The patch fixes this problem by making Cygwin use the Mac OS X case_ok()
instead of a modified Window's version.

Python/import.c

@@ -1377,16 +1377,13 @@ PyAPI_FUNC(int) _PyImport_IsScript(struct filedescr * fd)
 /* First we may need a pile of platform-specific header files; the sequence
  * of #if's here should match the sequence in the body of case_ok().
  */
-#if defined(MS_WINDOWS) || defined(__CYGWIN__)
+#if defined(MS_WINDOWS)
 #include <windows.h>
-#ifdef __CYGWIN__
-#include <sys/cygwin.h>
-#endif
 
 #elif defined(DJGPP)
 #include <dir.h>
 
-#elif defined(__MACH__) && defined(__APPLE__) && defined(HAVE_DIRENT_H)
+#elif (defined(__MACH__) && defined(__APPLE__) || defined(__CYGWIN__)) && defined(HAVE_DIRENT_H)
 #include <sys/types.h>
 #include <dirent.h>
 
@@ -1407,23 +1404,15 @@ case_ok(char *buf, int len, int namelen, char *name)
  * match the sequence just above.
  */
 
-/* MS_WINDOWS || __CYGWIN__ */
-#if defined(MS_WINDOWS) || defined(__CYGWIN__)
+/* MS_WINDOWS */
+#if defined(MS_WINDOWS)
 	WIN32_FIND_DATA data;
 	HANDLE h;
-#ifdef __CYGWIN__
-	char tempbuf[MAX_PATH];
-#endif
 
 	if (Py_GETENV("PYTHONCASEOK") != NULL)
 		return 1;
 
-#ifdef __CYGWIN__
-	cygwin32_conv_to_win32_path(buf, tempbuf);
-	h = FindFirstFile(tempbuf, &data);
-#else
 	h = FindFirstFile(buf, &data);
-#endif
 	if (h == INVALID_HANDLE_VALUE) {
 		PyErr_Format(PyExc_NameError,
 		  "Can't find file for module %.100s\n(filename %.300s)",
@@ -1450,8 +1439,8 @@ case_ok(char *buf, int len, int namelen, char *name)
 	}
 	return strncmp(ffblk.ff_name, name, namelen) == 0;
 
-/* new-fangled macintosh (macosx) */
-#elif defined(__MACH__) && defined(__APPLE__) && defined(HAVE_DIRENT_H)
+/* new-fangled macintosh (macosx) or Cygwin */
+#elif (defined(__MACH__) && defined(__APPLE__) || defined(__CYGWIN__)) && defined(HAVE_DIRENT_H)
 	DIR *dirp;
 	struct dirent *dp;
 	char dirname[MAXPATHLEN + 1];