[newlib-cygwin] Cygwin: Make sure newer apps get uname_x even when loading uname dynamically

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=532b91d24e9496c7988b2b1dda7fc0e8b161f782

commit 532b91d24e9496c7988b2b1dda7fc0e8b161f782
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Mon Dec 14 12:29:23 2020 +0100

    Cygwin: Make sure newer apps get uname_x even when loading uname dynamically
    
    if an application built after API version 334 loads uname dynamically,
    it actually gets the old uname, rather than the new uname_x.  Fix this by
    checking the apps API version in uname and call uname_x instead, if it's
    a newer app.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/include/cygwin/version.h | 3 +++
 winsup/cygwin/uname.cc                 | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/winsup/cygwin/include/cygwin/version.h b/winsup/cygwin/include/cygwin/version.h
index f21aba726..b39d0dbe9 100644
--- a/winsup/cygwin/include/cygwin/version.h
+++ b/winsup/cygwin/include/cygwin/version.h
@@ -74,6 +74,9 @@ details. */
 #define CYGWIN_VERSION_CHECK_FOR_EXTRA_TM_MEMBERS \
   (CYGWIN_VERSION_USER_API_VERSION_COMBINED >= 272)
 
+#define CYGWIN_VERSION_CHECK_FOR_UNAME_X \
+  (CYGWIN_VERSION_USER_API_VERSION_COMBINED >= 335)
+
 #define CYGWIN_VERSION_CYGWIN_CONV 181
 
 /* API_MAJOR 0.0: Initial version.  API_MINOR changes:
diff --git a/winsup/cygwin/uname.cc b/winsup/cygwin/uname.cc
index 350216681..48f7dda60 100644
--- a/winsup/cygwin/uname.cc
+++ b/winsup/cygwin/uname.cc
@@ -92,7 +92,14 @@ struct old_utsname
 extern "C" int
 uname (struct utsname *in_name)
 {
+  /* This occurs if the application fetches the uname symbol dynamically.
+     We must call uname_x for newer API versions, otherwise the idea of
+     struct utsname doesn't match. */
+  if (CYGWIN_VERSION_CHECK_FOR_UNAME_X)
+    return uname_x (in_name);
+
   struct old_utsname *name = (struct old_utsname *) in_name;
+
   __try
     {
       char *snp = strstr  (cygwin_version.dll_build_date, "SNP");