patch 9.0.1088: clang warns for unused variable

Problem:    Clang warns for unused variable.
Solution:   Adjust #ifdef. (John Marriott)
diff --git a/src/os_win32.c b/src/os_win32.c
index 4b23b1d..f12e75f 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -257,7 +257,9 @@
 
 static BOOL win8_or_later = FALSE;
 static BOOL win10_22H2_or_later = FALSE;
+#if !defined(FEAT_GUI_MSWIN) || defined(VIMDLL)
 static BOOL use_alternate_screen_buffer = FALSE;
+#endif
 
 /*
  * Get version number including build number
@@ -8395,7 +8397,7 @@
     }
 # endif
     use_alternate_screen_buffer = win10_22H2_or_later && p_rs && vtp_working
-    						&& !mch_getenv("VIM_TERMINAL");
+						&& !mch_getenv("VIM_TERMINAL");
     set_console_color_rgb();
 }
 
diff --git a/src/version.c b/src/version.c
index bcbc760..a7fd8d8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1088,
+/**/
     1087,
 /**/
     1086,