Patch libevent when building for Android (fix arc4random_addrandom)

depends/packages/libevent.mk

@@ -3,10 +3,17 @@ $(package)_version=2.1.8-stable
 $(package)_download_path=https://github.com/libevent/libevent/archive/
 $(package)_file_name=release-$($(package)_version).tar.gz
 $(package)_sha256_hash=316ddb401745ac5d222d7c529ef1eada12f58f6376a66c1118eee803cb70f83d
+$(package)_patches=fix_android_arc4random_addrandom.patch
 
+ifneq (,$(findstring android,$(host)))
+  define $(package)_preprocess_cmds
+    ./autogen.sh && patch -p1 < $($(package)_patch_dir)/fix_android_arc4random_addrandom.patch
+  endef
+else
   define $(package)_preprocess_cmds
     ./autogen.sh
   endef
+endif
 
 define $(package)_set_vars
   $(package)_config_opts=--disable-shared --disable-openssl --disable-libevent-regress --disable-samples

depends/patches/libevent/fix_android_arc4random_addrandom.patch

@@ -0,0 +1,68 @@
+From cadae3ab7abf45e61ecae8aac39d97d1f3cbd336 Mon Sep 17 00:00:00 2001
+From: Lawrence Nahum <lawrence@greenaddress.it>
+Date: Sun, 3 Dec 2017 22:56:09 +0100
+Subject: [PATCH] fixup
+
+---
+ configure.ac          | 1 +
+ evutil_rand.c         | 3 +++
+ include/event2/util.h | 4 ++--
+ 3 files changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 7528d37..3bb2121 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -341,6 +341,7 @@ dnl Checks for library functions.
+ AC_CHECK_FUNCS([ \
+   accept4 \
+   arc4random \
++  arc4random_addrandom \
+   arc4random_buf \
+   eventfd \
+   epoll_create1 \
+diff --git a/evutil_rand.c b/evutil_rand.c
+index 046a14b..3f0bf2c 100644
+--- a/evutil_rand.c
++++ b/evutil_rand.c
+@@ -191,6 +191,7 @@ evutil_secure_rng_get_bytes(void *buf, size_t n)
+ {
+ 	ev_arc4random_buf(buf, n);
+ }
++#ifdef HAVE_ARC4RANDOM_ADDRANDOM
+ 
+ void
+ evutil_secure_rng_add_bytes(const char *buf, size_t n)
+@@ -199,6 +200,8 @@ evutil_secure_rng_add_bytes(const char *buf, size_t n)
+ 	    n>(size_t)INT_MAX ? INT_MAX : (int)n);
+ }
+ 
++#endif
++
+ void
+ evutil_free_secure_rng_globals_(void)
+ {
+diff --git a/include/event2/util.h b/include/event2/util.h
+index dd4bbb6..a9a169d 100644
+--- a/include/event2/util.h
++++ b/include/event2/util.h
+@@ -841,7 +841,7 @@ int evutil_secure_rng_init(void);
+  */
+ EVENT2_EXPORT_SYMBOL
+ int evutil_secure_rng_set_urandom_device_file(char *fname);
+-
++#ifdef HAVE_ARC4RANDOM_ADDRANDOM
+ /** Seed the random number generator with extra random bytes.
+ 
+     You should almost never need to call this function; it should be
+@@ -858,7 +858,7 @@ int evutil_secure_rng_set_urandom_device_file(char *fname);
+  */
+ EVENT2_EXPORT_SYMBOL
+ void evutil_secure_rng_add_bytes(const char *dat, size_t datlen);
+-
++#endif
+ #ifdef __cplusplus
+ }
+ #endif
+-- 
+2.14.3