[devhelp] libdevhelp: explicitly link with libm for sqrt() in dh-window.c

[Frederic Peters <fpeters src gnome org>]

commit 386cf84a0424c4503f0797a9ecc08ef143d2b73f
Author: Alexandre Rostovtsev <tetromino gentoo org>
Date:   Fri Nov 23 02:33:53 2012 -0500

    libdevhelp: explicitly link with libm for sqrt() in dh-window.c
    
    Prevents linking failure when using GNU gold.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=688919

 configure.ac    |    3 +++
 src/Makefile.am |    3 ++-
 2 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index e9c9e87..8849c70 100644
--- a/configure.ac
+++ b/configure.ac
@@ -71,6 +71,9 @@ else
 fi
 AM_CONDITIONAL(WITH_WEBKIT2, test "x$with_webkit2" != xno)
 
+AC_CHECK_LIBM
+AC_SUBST(LIBM)
+
 PKG_CHECK_MODULES(DEVHELP, [
   gthread-2.0 >= 2.10.0
   gtk+-3.0 >= 3.4
diff --git a/src/Makefile.am b/src/Makefile.am
index e6b1716..419c31c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -107,7 +107,8 @@ libdevhelp_3_la_CFLAGS =				\
 
 libdevhelp_3_la_LIBADD =				\
 	$(LIBDEVHELP_LIBS)				\
-	$(ZLIB_LIBS)
+	$(ZLIB_LIBS)					\
+	$(LIBM)
 
 libdevhelp_3_la_LDFLAGS =				\
 	-no-undefined					\