pal: Explicitly add libm to build

Previously I was relying on SOFA to pull in libm despite PAL
using sin, cos etc. itself.

component.xml

@@ -3,7 +3,7 @@
 <!-- component.xml.  Generated from component.xml.in by configure. -->
 
 <component id="pal" support="S">
-  <version>0.1.4</version>
+  <version>0.1.5</version>
   <path>libraries/pal</path>
   <description>Position Astronomy Library</description>
   <abstract><p>

configure.ac

@@ -2,7 +2,7 @@ dnl    Process this file with autoconf to produce a configure script
 AC_REVISION($Revision: 27534 $)
 
 dnl    Initialisation: package name and version number
-AC_INIT(pal, 0.1.4, [email protected])
+AC_INIT(pal, 0.1.5, [email protected])
 
 dnl    Require autoconf-2.50 at least
 AC_PREREQ(2.50)
@@ -27,6 +27,9 @@ dnl    copysign and isblank are a c99 feature
 AC_CHECK_FUNCS(copysign)
 AC_CHECK_FUNCS(isblank)
 
+# Need the math library
+AC_CHECK_LIB([m],[sin])
+
 dnl    Declare the build and use dependencies for this package
 STAR_DECLARE_DEPENDENCIES(build, [sofa starutil])
 STAR_DECLARE_DEPENDENCIES(link,  [sofa starutil])

pal.news

@@ -4,6 +4,10 @@ The Starlink Positional Astronomy Library (PAL) is a C implementation of the
 SLALIB API. It is distributed under the GPL and uses the SOFA library wherever
 possible.
 
+V0.1.5
+
+Explcitly look for libm rather than relying on SOFA to pull it in.
+
 V0.1.4
 
 Check for isblank() function and fall back if it is missing.