From Alberto Luaces, "the new changes in osgAnimation showed some errors on the Cygwin

platform:

1 - osgAnimation/StatsHandler includes <cmath>, but on Cygwin only std::isnan
is defined that way. I changed it to <math.h> as it is done in the rest of
the OSG.

2 - Pulling some osgViewer headers from the same file in osgAnimation makes
the former a new dependency. Thus, I got errors at osgAnimation linking time.
I wonder why nobody noticed this on other platforms. I have updated the
CMakeLists.txt file in order to link to the needed libraries, and

3 - I have updated the openscenegraph-osgAnimation.pc.in file accordingly."

packaging/pkgconfig/openscenegraph-osgAnimation.pc.in

@@ -8,7 +8,7 @@ includedir=${prefix}/include
 Name: openscenegraph-osgAnimation
 Description: Skinning and morphing library for Openscenegraph
 Version: @OPENSCENEGRAPH_VERSION@
-Requires: openscenegraph-osg openthreads
+Requires: openscenegraph-osg openscenegraph-osgText openscenegraph-osgGA openscenegraph-osgViewer openthreads
 Conflicts:
 Libs: -L${libdir} -losgAnimation
 Cflags: -I${includedir}