more cleanups based on sparse reports, added "make sparse" Daniel

* Makefile.am globals.c parserInternals.c xmlreader.c xmlunicode.c
  xmlwriter.c: more cleanups based on sparse reports, added
  "make sparse"
Daniel
diff --git a/Makefile.am b/Makefile.am
index 1485e51..ef043cb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1135,3 +1135,6 @@
 
 tst: tst.c
 	$(CC) $(CFLAGS) -Iinclude -o tst tst.c .libs/libxml2.a -lpthread -lm -lz
+
+sparse: clean
+	$(MAKE) CC=cgcc