[gnome-software] trivial: Use LT_LIB_M

[Richard Hughes <rhughes src gnome org>]

commit 65b640cbb942fc8baa134a35e02418d3528dd498
Author: Richard Hughes <richard hughsie com>
Date:   Thu Jul 28 14:38:59 2016 +0100

    trivial: Use LT_LIB_M

 configure.ac        |    5 +++++
 doc/api/Makefile.am |    1 +
 src/Makefile.am     |    6 +++---
 3 files changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index f99ec50..ecb6513 100644
--- a/configure.ac
+++ b/configure.ac
@@ -71,6 +71,11 @@ PKG_CHECK_MODULES(SOUP, libsoup-2.4 >= 2.51.92)
 PKG_CHECK_MODULES(GSETTINGS_DESKTOP_SCHEMAS, gsettings-desktop-schemas >= 3.11.5)
 PKG_CHECK_MODULES(LIBSECRET, libsecret-1)
 AC_PATH_PROG(APPSTREAM_UTIL, [appstream-util], [unfound])
+
+# use -lm
+LT_LIB_M
+AC_SUBST(LIBM)
+
 AC_ARG_ENABLE(man,
               [AS_HELP_STRING([--enable-man],
                               [generate man pages [default=auto]])],,
diff --git a/doc/api/Makefile.am b/doc/api/Makefile.am
index 7cf7bbc..293e844 100644
--- a/doc/api/Makefile.am
+++ b/doc/api/Makefile.am
@@ -76,6 +76,7 @@ GTKDOC_LIBS=                                                  \
        $(GLIB_LIBS)                                            \
        $(POLKIT_LIBS)                                          \
        $(APPSTREAM_LIBS)                                       \
+       $(LIBM)                                                 \
        $(LIBSECRET_LIBS)                                       \
        $(GTK_LIBS)                                             \
        $(top_builddir)/src/gnome_software-gs-app-list.o        \
diff --git a/src/Makefile.am b/src/Makefile.am
index da8f016..b8677dd 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -127,7 +127,7 @@ gnome_software_cmd_LDADD =                          \
        $(LIBSECRET_LIBS)                               \
        $(GLIB_LIBS)                                    \
        $(GTK_LIBS)                                     \
-       -lm
+       $(LIBM)
 
 gnome_software_cmd_CFLAGS =                            \
        $(WARN_CFLAGS)
@@ -280,7 +280,7 @@ gnome_software_LDADD =                                      \
        $(PACKAGEKIT_LIBS)                              \
        $(GNOME_DESKTOP_LIBS)                           \
        $(POLKIT_LIBS)                                  \
-       -lm
+       $(LIBM)
 
 gnome_software_CFLAGS =                                        \
        -DLIBEXECDIR=\"$(libexecdir)\"                  \
@@ -353,7 +353,7 @@ gs_self_test_LDADD =                                                \
        $(LIBSECRET_LIBS)                                       \
        $(GLIB_LIBS)                                            \
        $(GTK_LIBS)                                             \
-       -lm
+       $(LIBM)
 
 gs_self_test_CFLAGS = $(WARN_CFLAGS)