dropbear: Patch away hard link usage

Fixes #1082.

packages/dropbear/build.sh

@@ -2,6 +2,7 @@ TERMUX_PKG_HOMEPAGE=https://matt.ucc.asn.au/dropbear/dropbear.html
 TERMUX_PKG_DESCRIPTION="Small SSH server and client"
 TERMUX_PKG_DEPENDS="libutil"
 TERMUX_PKG_VERSION=2017.75
+TERMUX_PKG_REVISION=1
 TERMUX_PKG_SRCURL=https://matt.ucc.asn.au/dropbear/releases/dropbear-${TERMUX_PKG_VERSION}.tar.bz2
 TERMUX_PKG_SHA256=6cbc1dcb1c9709d226dff669e5604172a18cf5dbf9a201474d5618ae4465098c
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--disable-syslog --disable-utmp --disable-utmpx --disable-wtmp"

packages/dropbear/gensignkey.c.patch

@@ -0,0 +1,28 @@
+diff -u -r ../dropbear-2017.75/gensignkey.c ./gensignkey.c
+--- ../dropbear-2017.75/gensignkey.c	2017-05-18 16:47:01.000000000 +0200
++++ ./gensignkey.c	2017-06-13 23:50:59.888597482 +0200
+@@ -137,6 +137,16 @@
+ 		goto out;
+ 	}
+ 
++#ifdef __ANDROID__
++	/* Hard links are not possible and renam. */
++	if (skip_exist && access(filename, F_OK) == 0) {
++		/* Ok. */
++	} else if (rename(fn_temp, filename) < 0) {
++		dropbear_log(LOG_ERR, "Failed moving key file to %s: %s", filename,
++			strerror(errno));
++		ret = DROPBEAR_FAILURE;
++	}
++#else
+ 	if (link(fn_temp, filename) < 0) {
+ 		/* If generating keys on connection (skipexist) it's OK to get EEXIST 
+ 		- we probably just lost a race with another connection to generate the key */
+@@ -148,6 +158,7 @@
+ 			goto out;
+ 		}
+ 	}
++#endif
+ 
+ out:
+ 	if (buf) {