autofs-5.1.4 - fix libresolv configure check

From: Ian Kent <raven@themaw.net>

The libresolv functions are not found by AC_CHECK_LIB() unless
they are prefixed with "__".

So change the library check to also look for __<function> during
the check.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 CHANGELOG    |    1 +
 configure    |   41 +++++++++++++++++++++++++++++++++++++++++
 configure.in |    2 +-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG b/CHANGELOG
index a7bb89dc..dbfb8389 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -13,6 +13,7 @@ xx/xx/2018 autofs-5.1.5
 - fix monotonic_elapsed.
 - Makefiles.rules: remove 'samples' from SUBDIRS.
 - dont allow trailing slash in master map mount points.
+- fix libresolv configure check.
 
 19/12/2017 autofs-5.1.4
 - fix spec file url.
diff --git a/configure b/configure
index 2d517aac..5c8aae30 100755
--- a/configure
+++ b/configure
@@ -4821,6 +4821,47 @@ fi
 $as_echo "$ac_cv_lib_resolv_res_query" >&6; }
 if test "x$ac_cv_lib_resolv_res_query" = xyes; then :
   LIBRESOLV="-lresolv"
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __res_query in -lresolv" >&5
+$as_echo_n "checking for __res_query in -lresolv... " >&6; }
+if ${ac_cv_lib_resolv___res_query+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lresolv  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char __res_query ();
+int
+main ()
+{
+return __res_query ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_resolv___res_query=yes
+else
+  ac_cv_lib_resolv___res_query=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_resolv___res_query" >&5
+$as_echo "$ac_cv_lib_resolv___res_query" >&6; }
+if test "x$ac_cv_lib_resolv___res_query" = xyes; then :
+  LIBRESOLV="-lresolv"
+fi
+
 fi
 
 
diff --git a/configure.in b/configure.in
index d74775cc..4d1208f5 100644
--- a/configure.in
+++ b/configure.in
@@ -217,7 +217,7 @@ AC_SUBST(NSL_LIBS)
 NSL_CFLAGS=""
 ])
 
-AC_CHECK_LIB(resolv, res_query, LIBRESOLV="-lresolv")
+AC_CHECK_LIB(resolv, res_query, LIBRESOLV="-lresolv", AC_CHECK_LIB(resolv, __res_query, LIBRESOLV="-lresolv"))
 AC_SUBST(LIBRESOLV)
 
 #