Really fix the libevent make distcheck problem. The main issue is how

libevent creates its event-config.h during "make all" (vs. during
configure).  The prior method around this didn't work because it wrote
an event-config.h.in in the source tree -- a Bad Idea(tm).  The new
way uses AC_CONFIG_COMMAND to get stuff executed at the end of
config.status to create event-config.h.  This seems to work properly
during make distcheck.

This commit was SVN r23975.

opal/mca/event/libevent207/Makefile.am

@@ -45,7 +45,6 @@ headers += libevent/event.h libevent/evutil.h libevent/util-internal.h \
            libevent/include/event2/dns_struct.h \
            libevent/include/event2/event_compat.h \
            libevent/include/event2/event_struct.h \
-           libevent/include/event2/event-config.h \
            libevent/include/event2/event.h \
            libevent/include/event2/http_compat.h \
            libevent/include/event2/http_struct.h \
@@ -61,6 +60,8 @@ headers += libevent/event.h libevent/evutil.h libevent/util-internal.h \
            libevent/include/event2/util.h
 opaldir = $(includedir)/openmpi/$(subdir)
 nobase_opal_HEADERS = $(headers)
+
+nobase_nodist_opal_HEADERS = libevent/include/event2/event-config.h
 endif
 
 # Make the output library in this directory, and name it either

opal/mca/event/libevent207/configure.m4

@@ -127,13 +127,11 @@ AC_DEFUN([MCA_opal_event_libevent207_CONFIG],[
            # other things are built before the event framework that
            # end up including event-config.h).  The steps below were
            # copied from libevent's Makefile.am.
-           file="$basedir/libevent/include/event2/event-config.h"
-           mkdir -p "`dirname $OMPI_TOP_SRCDIR/$file`"
-           AS_IF([test ! -d "`dirname $OMPI_TOP_SRCDIR/$file`"],
-                 [AC_MSG_WARN([Failed to mkdir `dirname $file`])
-                  AC_MSG_ERROR([Cannot continue])])
-
-           cat > "$OMPI_TOP_SRCDIR/$file.in" <<EOF
+           AC_CONFIG_COMMANDS([opal/mca/event/libevent207/libevent/include/event2/event-config.h],
+                              [basedir="opal/mca/event/libevent207"
+                               file="$basedir/libevent/include/event2/event-config.h"
+                               rm -f "$file.new"
+                               cat > "$file.new" <<EOF
 /* event2/event-config.h
  *
  * This file was generated by autoconf when libevent was built, and
@@ -149,11 +147,20 @@ AC_DEFUN([MCA_opal_event_libevent207_CONFIG],[
 #define _EVENT2_EVENT_CONFIG_H_
 EOF
 
-           sed -e 's/#define /#define _EVENT_/' \
-               -e 's/#undef /#undef _EVENT_/' \
-               -e 's/#ifndef /#ifndef _EVENT_/' < "$OMPI_TOP_BUILDDIR/$basedir/libevent/config.h" >> "$OMPI_TOP_SRCDIR/$file.in"
-           echo "#endif" >> "$OMPI_TOP_SRCDIR/$file.in"
-           AC_CONFIG_FILES([$file])
+                               sed -e 's/#define /#define _EVENT_/' \
+                                   -e 's/#undef /#undef _EVENT_/' \
+                                   -e 's/#ifndef /#ifndef _EVENT_/' < "$basedir/libevent/config.h" >> "$file.new"
+                               echo "#endif" >> "$file.new"
+
+                               # Only make a new .h file if the
+                               # contents haven't changed
+                               diff -q $file "$file.new" > /dev/null 2> /dev/null
+                               if test "$?" = "0"; then
+                                   echo $file is unchanged
+                               else
+                                   cp "$file.new" $file
+                                   rm -f "$file.new"
+                               fi])
 
            # Must set this variable so that the framework m4 knows
            # what file to include in opal/mca/event/event.h