[newlib-cygwin/main] Cygwin: add compile warning if ENOSHARE or ECASECLASH is used

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=6f996d7751bf25f7e4282da631eb79b93662e484

commit 6f996d7751bf25f7e4282da631eb79b93662e484
Author:     Christian Franke <christian.franke@t-online.de>
AuthorDate: Tue Feb 27 13:03:08 2024 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Wed Feb 28 09:59:07 2024 +0100

    Cygwin: add compile warning if ENOSHARE or ECASECLASH is used
    
    These errno values are no longer used by Cygwin.
    
    Signed-off-by: Christian Franke <christian.franke@t-online.de>

Diff:
---
 newlib/libc/include/sys/errno.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/newlib/libc/include/sys/errno.h b/newlib/libc/include/sys/errno.h
index f1509712e48e..7199db0d2e35 100644
--- a/newlib/libc/include/sys/errno.h
+++ b/newlib/libc/include/sys/errno.h
@@ -176,9 +176,9 @@ extern __IMPORT char *program_invocation_short_name;
 #ifdef __LINUX_ERRNO_EXTENSIONS__
 #define ENOMEDIUM 135   /* No medium (in tape drive) */
 #endif
-#ifdef __CYGWIN__
-#define ENOSHARE 136    /* No such host or network path */
-#define ECASECLASH 137  /* Filename exists with different case */
+#if defined(__CYGWIN__) && !defined(__INSIDE_CYGWIN__)
+#define ENOSHARE (_Pragma("GCC warning \"'ENOSHARE' is no longer used by Cygwin\"") 136)
+#define ECASECLASH (_Pragma("GCC warning \"'ECASECLASH' is no longer used by Cygwin\"") 137)
 #endif
 #define EILSEQ 138		/* Illegal byte sequence */
 #define EOVERFLOW 139	/* Value too large for defined data type */