No <glob.h> in the Android NDK

So don't bother building libxml2 programs for Android, we have no need for
them, there is no way to run them on normal devices, etc. While at it, don't
bother with scripts, manpages or "data" either. We just want the library.

Change-Id: Ic6553c4ed5b51feab40fed6bd62fd10795e9acf9

external/libxml2/libxml2-android.patch

@@ -25,3 +25,14 @@
  
  #elif defined(NAN) && defined(__STDC_IEC_559__)
 
+--- misc/libxml2-2.7.6/Makefile.in
++++ misc/build/libxml2-2.7.6/Makefile.in
+@@ -1635,7 +1635,7 @@
+ check-am: all-am
+ check: $(BUILT_SOURCES)
+ 	$(MAKE) $(AM_MAKEFLAGS) check-recursive
+-all-am: Makefile $(LTLIBRARIES) $(PROGRAMS) $(SCRIPTS) $(MANS) $(DATA) \
++all-am: Makefile $(LTLIBRARIES) \
+ 		config.h
+ install-binPROGRAMS: install-libLTLIBRARIES
+