[PATCH] [configure.ac]: two small fixes

[Chengwei Yang]

This commit does polish a little to configure.ac.

1. add configure option for coverage-profiling
2. assign the default value to with_xml

Both of them are to avoid null variable in configure summary like below:
    ...
    gcc coverage profiling:
    ...
    Using XML parser:
    ...

Signed-off-by: Chengwei Yang <chengwei.yang at intel.com>
---
 configure.ac |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index f351fde..fb3604a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -155,10 +155,11 @@ AC_ARG_ENABLE(inotify, AS_HELP_STRING([--enable-inotify],[build with inotify sup
 AC_ARG_ENABLE(kqueue, AS_HELP_STRING([--enable-kqueue],[build with kqueue support]),enable_kqueue=$enableval,enable_kqueue=auto)
 AC_ARG_ENABLE(console-owner-file, AS_HELP_STRING([--enable-console-owner-file],[enable console owner file]),enable_console_owner_file=$enableval,enable_console_owner_file=auto)
 AC_ARG_ENABLE(userdb-cache, AS_HELP_STRING([--enable-userdb-cache],[build with userdb-cache support]),enable_userdb_cache=$enableval,enable_userdb_cache=yes)
+AC_ARG_ENABLE(coverage-profiling, AS_HELP_STRING([--enable-coverage-profiling],[build with coverage profiling]),[enable_compiler_coverage=$enableval],[enable_compiler_coverage=no])
 AC_ARG_ENABLE(launchd, AS_HELP_STRING([--enable-launchd],[build with launchd auto-launch support]),enable_launchd=$enableval,enable_launchd=auto)
 AC_ARG_ENABLE(systemd, AS_HELP_STRING([--enable-systemd],[build with systemd at_console support]),enable_systemd=$enableval,enable_systemd=auto)
 
-AC_ARG_WITH(xml, AS_HELP_STRING([--with-xml=[libxml/expat]],[XML library to use (libxml may be named libxml2 on some systems)]))
+AC_ARG_WITH(xml, AS_HELP_STRING([--with-xml=[libxml/expat]],[XML library to use (libxml may be named libxml2 on some systems), @<:@default=expat@:>@]),[with_xml=$withval],[with_xml=expat])
 AC_ARG_WITH(init-scripts, AS_HELP_STRING([--with-init-scripts=[redhat]],[Style of init scripts to install]))
 AC_ARG_WITH(session-socket-dir, AS_HELP_STRING([--with-session-socket-dir=[dirname]],[Where to put sockets for the per-login-session message bus]))
 AC_ARG_WITH(test-socket-dir, AS_HELP_STRING([--with-test-socket-dir=[dirname]],[Where to put sockets for make check]))
-- 
1.7.9.5