added patch to disable libgrcypt docs

android/external/Makefile

@@ -149,6 +149,7 @@ libgcrypt/configure: libgcrypt.src.stamp libgcrypt/configure.ac
 	cd libgcrypt && ./autogen.sh
 
 libgcrypt/Makefile: libgcrypt/configure 
+	-patch -N -p1 --reject-file=- libgcrypt/Makefile.am libgcrypt-disable-docs.patch
 	cd libgcrypt && \
 		CC="$(CC)" AR="$(AR)" RANLIB=$(RANLIB) CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)" \
 			./configure \

android/external/libgcrypt-disable-docs.patch

@@ -0,0 +1,13 @@
+--- a/libgcrypt/Makefile.am	2015-09-08 08:29:55.000000000 +0200
++++ b/libgcrypt/Makefile.am	2016-08-23 17:16:50.712565999 +0200
+@@ -24,8 +24,8 @@
+ # (A suitable gitlog-to-changelog script can be found in GnuPG master.)
+ GITLOG_TO_CHANGELOG=gitlog-to-changelog
+ 
+-DIST_SUBDIRS = m4 compat mpi cipher random src doc tests
+-SUBDIRS =         compat mpi cipher random src doc tests
++DIST_SUBDIRS = m4 compat mpi cipher random src
++SUBDIRS =         compat mpi cipher random src
+ 
+ EXTRA_DIST = autogen.sh autogen.rc README.GIT LICENSES      	           \
+              ChangeLog-2011 build-aux/ChangeLog-2011 doc/ChangeLog-2011    \