[empathy] build: use an autoconf macro to get to -lm

[Frederic Peters <fpeters src gnome org>]

commit 18009c7071732d29dd5a6eba8ef7f6b53c91e4d3
Author: FrÃdÃric PÃters <fpeters 0d be>
Date:   Wed Aug 31 09:34:12 2011 +0200

    build: use an autoconf macro to get to -lm

 configure.ac           |    3 +++
 libempathy/Makefile.am |    2 +-
 src/Makefile.am        |    4 ++--
 3 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 810b735..e235118 100644
--- a/configure.ac
+++ b/configure.ac
@@ -167,6 +167,9 @@ AC_SUBST(LDFLAGS)
 # Pkg-Config dependency checks
 # -----------------------------------------------------------
 
+AC_CHECK_LIBM
+AC_SUBST(LIBM)
+
 PKG_CHECK_MODULES(EMPATHY,
 [
    dbus-glib-1
diff --git a/libempathy/Makefile.am b/libempathy/Makefile.am
index 21a5820..3cd971a 100644
--- a/libempathy/Makefile.am
+++ b/libempathy/Makefile.am
@@ -128,7 +128,7 @@ libempathy_la_LIBADD =		\
 	$(NETWORK_MANAGER_LIBS) \
 	$(CONNMAN_LIBS) \
 	$(UDEV_LIBS) \
-	-lm
+	$(LIBM)
 
 check_c_sources = \
     $(libempathy_handwritten_source)
diff --git a/src/Makefile.am b/src/Makefile.am
index 6be4b9e..cc4eebe 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -12,7 +12,7 @@ CPPFLAGS_COMMON =					\
 	$(WARN_CFLAGS)					\
 	$(NULL)
 
-AM_LDFLAGS = -lm
+AM_LDFLAGS = $(LIBM)
 AM_CPPFLAGS =						\
 	$(CPPFLAGS_COMMON)				\
 	$(LIBCHAMPLAIN_CFLAGS)				\
@@ -130,7 +130,7 @@ empathy_av_SOURCES = \
 nodist_empathy_av_SOURCES = $(BUILT_SOURCES)
 
 empathy_av_CFLAGS = $(EMPATHY_AV_CFLAGS)
-empathy_av_LDFLAGS = $(EMPATHY_AV_LIBS) -lm
+empathy_av_LDFLAGS = $(EMPATHY_AV_LIBS) $(LIBM)
 
 empathy_auth_client_SOURCES =						\
 	empathy-auth-client.c \