* acgeneral.m4: Report the update status of the cache better;

show diffs if an unwriteable cache gets updated, for manually
configuring the Mac config.cache.
* configure:  Update with this acgeneral.m4.

[This change, or one very close to it, was submitted for autoconf 2.2.]

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@5168 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/util/autoconf/acgeneral.m4 b/src/util/autoconf/acgeneral.m4
index b7e6bc3fd1808c11078247bc10c5be6917d90cd9..102b0bdd008d838d11bc36e0c55c6d1f15963b55 100644 (file)
--- a/src/util/autoconf/acgeneral.m4
+++ b/src/util/autoconf/acgeneral.m4
@@ -881,9 +881,7 @@ fi
 
 dnl AC_CACHE_SAVE()
 define(AC_CACHE_SAVE,
-[if test -w $cache_file; then
-echo "updating cache $cache_file"
-cat > $cache_file <<\EOF
+[cat > $cache_file.$$ <<\EOF
 # This file is a shell script that caches the results of configure
 # tests run on this system so they can be shared between configure
 # scripts and configure runs.  It is not useful on other systems.
@@ -906,11 +904,20 @@ dnl Allow a site initialization script to override cache values.
 # with their high bit set.
 (set) 2>&1 | tr '\201-\377' '\001-\177' |
   sed -n "s/^\([a-zA-Z0-9_]*_cv_[a-zA-Z0-9_]*\)=\(.*\)/: \${\1='\2'}/p" \
-  >> $cache_file
+  >> $cache_file.$$
 changequote([, ])dnl
+if cmp -s $cache_file $cache_file.$$; then
+  true
 else
-echo "not updating unwritable cache $cache_file"
+  if test -w $cache_file; then
+    echo "updating cache $cache_file"
+    cat $cache_file.$$ > $cache_file
+  else
+    echo "not updating unwritable cache $cache_file"
+    diff $cache_file $cache_file.$$
+  fi
 fi
+rm -f $cache_file.$$
 ])
 
 dnl The name of shell var CACHE-ID must contain `_cv_' in order to get saved.

diff --git a/src/util/autoconf/configure b/src/util/autoconf/configure
index 97345c99e8fa348a0630ac27d1070fd60c1b28e1..adff411ccf78198a5d7a9a59102c912a811423ff 100644 (file)
--- a/src/util/autoconf/configure
+++ b/src/util/autoconf/configure
@@ -549,9 +549,7 @@ if test -f $srcdir/standards.texi; then
 fi
 
 trap '' 1 2 15
-if test -w $cache_file; then
-echo "updating cache $cache_file"
-cat > $cache_file <<\EOF
+cat > $cache_file.$$ <<\EOF
 # This file is a shell script that caches the results of configure
 # tests run on this system so they can be shared between configure
 # scripts and configure runs.  It is not useful on other systems.
@@ -572,10 +570,19 @@ EOF
 # with their high bit set.
 (set) 2>&1 | tr '\201-\377' '\001-\177' |
   sed -n "s/^\([a-zA-Z0-9_]*_cv_[a-zA-Z0-9_]*\)=\(.*\)/: \${\1='\2'}/p" \
-  >> $cache_file
+  >> $cache_file.$$
+if cmp -s $cache_file $cache_file.$$; then
+  true
 else
-echo "not updating unwritable cache $cache_file"
+  if test -w $cache_file; then
+    echo "updating cache $cache_file"
+    cat $cache_file.$$ > $cache_file
+  else
+    echo "not updating unwritable cache $cache_file"
+    diff $cache_file $cache_file.$$
+  fi
 fi
+rm -f $cache_file.$$
 
 trap 'rm -fr conftest* confdefs* core $ac_clean_files; exit 1' 1 2 15