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

[Alberts Muktupāvels <muktupavels src gnome org>]

commit f82ddbf906851c234b5c25fdecd796105c0ef94b
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Sep 30 20:37:08 2015 +0300

    use LT_LIB_M to find the math library

 configure.ac                                |    1 +
 gnome-flashback/libsound-applet/Makefile.am |    4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 6c9c5a7..d9a41af 100644
--- a/configure.ac
+++ b/configure.ac
@@ -54,6 +54,7 @@ dnl Initialize libtool
 dnl **************************************************************************
 
 LT_INIT
+LT_LIB_M
 
 dnl **************************************************************************
 dnl Check for required programs
diff --git a/gnome-flashback/libsound-applet/Makefile.am b/gnome-flashback/libsound-applet/Makefile.am
index 75a22b6..d3a2624 100644
--- a/gnome-flashback/libsound-applet/Makefile.am
+++ b/gnome-flashback/libsound-applet/Makefile.am
@@ -31,9 +31,9 @@ libsound_applet_la_LDFLAGS = \
        $(NULL)
 
 libsound_applet_la_LIBADD = \
-       -lm \
-       $(SOUND_APPLET_LIBS) \
        gvc/libgvc.la \
+       $(SOUND_APPLET_LIBS) \
+       $(LIBM) \
        $(NULL)
 
 -include $(top_srcdir)/git.mk