[gnome-panel] use LT_LIB_M to find the math library

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 900be962c13ef5c6efd56989a12cef6614551271
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Sep 30 20:33:55 2015 +0300

    use LT_LIB_M to find the math library

 applets/clock/Makefile.am |    5 +++--
 configure.ac              |    1 +
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/applets/clock/Makefile.am b/applets/clock/Makefile.am
index 362b782..5013fc0 100644
--- a/applets/clock/Makefile.am
+++ b/applets/clock/Makefile.am
@@ -67,11 +67,12 @@ libclock_applet_la_CFLAGS = \
 libclock_applet_la_LIBADD = \
        ../../libpanel-applet/libpanel-applet.la        \
        ../../gnome-panel/libpanel-util/libpanel-util.la        \
+       libsystem-timezone.la \
        $(CLOCK_LIBS)                                   \
        $(CLOCK_EDS_LIBS)                                       \
        $(LIBPANEL_APPLET_LIBS)                         \
-       libsystem-timezone.la                           \
-       -lm
+       $(LIBM) \
+       $(NULL)
 
 libclock_applet_la_LDFLAGS = \
        -module -avoid-version \
diff --git a/configure.ac b/configure.ac
index 9081b0f..f5fa006 100644
--- a/configure.ac
+++ b/configure.ac
@@ -55,6 +55,7 @@ dnl **************************************************************************
 
 LT_PREREQ([2.2.6])
 LT_INIT([dlopen disable-static])
+LT_LIB_M
 
 # Before making a release, the LT_VERSION string should be modified.
 # The string is of the form C:R:A.