another patch from Kenneth Haley for Mingw, c.f. #128787 Daniel

* configure.in Makefile.am: another patch from Kenneth Haley
  for Mingw, c.f. #128787
Daniel
diff --git a/Makefile.am b/Makefile.am
index cedd520..d40f253 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -15,7 +15,7 @@
 bin_SCRIPTS=xml2-config
 
 lib_LTLIBRARIES = libxml2.la
-libxml2_la_LIBADD = @THREAD_LIBS@ @Z_LIBS@ $(ICONV_LIBS) -lm
+libxml2_la_LIBADD = @THREAD_LIBS@ @Z_LIBS@ $(ICONV_LIBS) @M_LIBS@ @WIN32_EXTRA_LIBADD@
 
 libxml2_la_LDFLAGS = -version-info @LIBXML_VERSION_INFO@
 
@@ -40,7 +40,7 @@
 endif
 
 DEPS = $(top_builddir)/libxml2.la
-LDADDS = @STATIC_BINARIES@ $(top_builddir)/libxml2.la @THREAD_LIBS@ @Z_LIBS@ $(ICONV_LIBS) -lm @WIN32_EXTRA_LIBADD@
+LDADDS = @STATIC_BINARIES@ $(top_builddir)/libxml2.la @THREAD_LIBS@ @Z_LIBS@ $(ICONV_LIBS) @M_LIBS@ @WIN32_EXTRA_LIBADD@
 
 
 man_MANS = xml2-config.1 libxml.3
@@ -78,7 +78,7 @@
 testC14N_DEPENDENCIES = $(DEPS)
 testC14N_LDADD= $(LDADDS)
 
-testThreads_SOURCES=testThreads.c
+testThreads_SOURCES=testThreads@THREADS_W32@.c
 testThreads_LDFLAGS = 
 testThreads_DEPENDENCIES = $(DEPS)
 testThreads_LDADD= $(LDADDS)