Produce a shared library rather than an executable and introduce an
install target.

Signed-off-by: Lucas C. Villa Real <lucasvr@gobolinux.org>

diff --git a/Makefile b/Makefile
index b1a8ed7..e8ed746 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,15 @@
-all: xmltest
+TARGET = libtinyxml.so
+
+all: ${TARGET} xmltest
+
+install:
+	install ${TARGET} ${DESTDIR}/lib
+	install *.h ${DESTDIR}/include
+
 xmltest: xmltest.cpp tinyxml2.cpp tinyxml2.h
+
+${TARGET}: tinyxml2.o
+	${CXX} -shared -o $@ $<
+
 clean:
-	rm -f *.o xmltest
+	rm -f *.o xmltest ${TARGET}