patch 8.2.2437: deprecation warnings with default configuration

Problem:    Deprecation warnings with default configuration.
Solution:   Add -Wno-deprecated-declarations.
diff --git a/src/auto/configure b/src/auto/configure
index 9d76f89..12d8f24 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -4482,7 +4482,7 @@
 
 if test -z "$CFLAGS"; then
   CFLAGS="-O"
-  test "$GCC" = yes && CFLAGS="-O2 -fno-strength-reduce -Wall"
+  test "$GCC" = yes && CFLAGS="-O2 -fno-strength-reduce -Wall -Wno-deprecated-declarations"
 fi
 if test "$GCC" = yes; then
     gccversion=`$CC -dumpversion`