krb5 commit [krb5-1.15]: Force autoconf rebuild in maintainer rules

https://github.com/krb5/krb5/commit/c1e18e9dfa4c0b406322100ce22815f48b760367
commit c1e18e9dfa4c0b406322100ce22815f48b760367
Author: Greg Hudson <[email protected]>
Date:   Tue Mar 14 19:39:38 2017 -0400

    Force autoconf rebuild in maintainer rules
    
    autoconf normally avoids recreating files that it does not consider
    obsolete.  Since it knows nothing about patchlevel.h (which we read at
    autoconf time using m4's esyscmd()), changes to patchlevel.h won't be
    reflected in configure unless another input to configure has changed,
    and the maintainer rule will re-run autoconf over and over again.  Fix
    this issue by passing the force flag to autoconf when we invoke it
    from the maintainer rule.
    
    (cherry picked from commit 7027788ae6adbd06d5a16de6ee62e489a4dca68b)
    
    ticket: 8560
    version_fixed: 1.15.2

 src/config/post.in |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/config/post.in b/src/config/post.in
index 77a9bff..7c7d86d 100644
--- a/src/config/post.in
+++ b/src/config/post.in
@@ -185,7 +185,7 @@ $(top_srcdir)/configure: @MAINT@ \
 		$(top_srcdir)/patchlevel.h \
 		$(top_srcdir)/aclocal.m4
 	(cd $(top_srcdir) && \
-		$(AUTOCONF) --include=$(CONFIG_RELTOPDIR) $(AUTOCONFFLAGS))
+		$(AUTOCONF) -f --include=$(CONFIG_RELTOPDIR) $(AUTOCONFFLAGS))
 
 RECURSE_TARGETS=all-recurse clean-recurse distclean-recurse install-recurse \
 	generate-files-mac-recurse \