do not reference strdup() ! trying to fix the libs of the various config

* globals.c: do not reference strdup() !
* configure.in libxml-2.0.pc.in: trying to fix the libs
  of the various config extraction modules
Daniel
diff --git a/configure.in b/configure.in
index cc4f0fb..819f83e 100644
--- a/configure.in
+++ b/configure.in
@@ -447,7 +447,8 @@
 		LIBS="${_libs}"
 		LDFLAGS="${_ldflags}"])]))
 fi
-XML_LIBS="-lxml2 $Z_LIBS $ICONV_LIBS -lm $LIBS"
+M_LIBS="-lm"
+XML_LIBS="-lxml2 $Z_LIBS $THREAD_LIBS $ICONV_LIBS $M_LIBS $LIBS"
 AC_SUBST(WITH_ICONV)
 
 AC_ARG_WITH(debug, [  --with-debug            Add the debugging module (on)])