(trunk) #2167 improve the autoconf libevent test: don't use the OS copy unless it's got evutil_vsnprintf()

configure.ac

@@ -170,16 +170,29 @@ dnl build our copy of libevent whether we use it or not,
 dnl because "make dist" needs its Makefiles to exist, and
 dnl AM_CONDITIONAL + AC_CONFIG_SUBDIRS don't seem to play nice
 AC_CONFIG_SUBDIRS([third-party/libevent])
-
+libevent_source=bundled
+AC_CHECK_LIB([event],[evutil_vsnprintf],
+             [libevent_found=yes],
+             [libevent_found=no],
+             [-levent])
 AC_CHECK_HEADER([event-config.h],
-                [libevent_source=system
-                 LIBEVENT_CPPFLAGS=""
-                 LIBEVENT_LIBS="-levent -lrt"],
-                [libevent_source=bundled
-                 AC_MSG_NOTICE([couldn't find event-config.h, so using our own copy of libevent from third-party/libevent/.])
-                 AC_MSG_NOTICE([if you are cross-compiling this is probably NOT what you want.])
-                 LIBEVENT_CPPFLAGS="-I\$(top_srcdir)/third-party/libevent -I\$(top_builddir)/third-party/libevent"
-                 LIBEVENT_LIBS="\$(top_builddir)/third-party/libevent/libevent.la"])
+                [libevent_headers_found=yes],
+                [libevent_headers_found=no])
+libevent_source=bundled
+if test "x$libevent_found" = "xyes" ; then
+    if test "x$libevent_headers_found" = "xyes"; then
+      libevent_source=system
+    fi
+fi
+if test "x$libevent_source" = "xbundled"; then
+    AC_MSG_NOTICE([couldn't find event-config.h, so using our own copy of libevent from third-party/libevent/.])
+    AC_MSG_NOTICE([if you are cross-compiling this is probably NOT what you want.])
+    LIBEVENT_CPPFLAGS="-I\$(top_srcdir)/third-party/libevent -I\$(top_builddir)/third-party/libevent"
+    LIBEVENT_LIBS="\$(top_builddir)/third-party/libevent/libevent.la"
+else
+    LIBEVENT_CPPFLAGS=""
+    LIBEVENT_LIBS="-levent -lrt"
+fi
 AC_SUBST(LIBEVENT_CPPFLAGS)
 AC_SUBST(LIBEVENT_LIBS)