[lasem] Ensure we link against the standard math library explicitly

[J.H.M. Dassen (Ray) <jdassen src gnome org>]

commit 3f95f9fc319f8a9928b853173aa50855a8ee77b9
Author: J.H.M. Dassen (Ray) <jdassen debian org>
Date:   Sat Nov 3 17:46:46 2012 +0100

    Ensure we link against the standard math library explicitly

 configure.ac |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 342f20b..f1dcaa5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -43,6 +43,10 @@ PKG_CHECK_MODULES(LASEM, [gobject-2.0
 			  cairo >= 1.2
 			  pangocairo >= 1.16.0
 			  libxml-2.0])
+# We use functions from the standard math library; it doesn't have
+# a pkgconfig file.
+LASEM_LIBS="${LASEM_LIBS} -lm"
+
 AC_SUBST(LASEM_CFLAGS)
 AC_SUBST(LASEM_LIBS)