configure.in: fail abstract socket test gracefully when cross-compiling

 * configure.in: only run AC_CACHE_CHECK if enable_abstract_sockets=auto
 * configure.in: warn that, when cross-compiling, we're unable to detect
                 abstract sockets availability automatically

Signed-off-by: Thiago Macieira <thiago@kde.org>

diff --git a/configure.in b/configure.in
index fd972b4..9e047ea 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -814,8 +814,9 @@ AC_CHECK_FUNCS(getpeerucred getpeereid)
 
 #### Abstract sockets
 
-if ! test x$enable_abstract_sockets = xno; then
+if test x$enable_abstract_sockets = xauto; then
 AC_LANG_PUSH(C)
+warn_on_xcompile=no
 AC_CACHE_CHECK([abstract socket namespace],
                ac_cv_have_abstract_sockets,
                [AC_RUN_IFELSE([AC_LANG_PROGRAM(
@@ -855,8 +856,15 @@ AC_CACHE_CHECK([abstract socket namespace],
     exit (0);
 ]])],
               [ac_cv_have_abstract_sockets=yes],
-              [ac_cv_have_abstract_sockets=no]
+              [ac_cv_have_abstract_sockets=no],
+              [
+                ac_cv_have_abstract_sockets=no
+                warn_on_xcompile=yes
+              ]
 )])
+if test x$warn_on_xcompile = xyes ; then
+  AC_MSG_WARN([Cannot check for abstract sockets when cross-compiling, please use --enable-abstract-sockets])
+fi
 AC_LANG_POP(C)
 fi