Defer checking for arc4random and friends until libcrypto is found,
fixes segv due to portable libressl/opensmtpd and arc4random<->RAND_bytes.

See http://marc.info/?l=openssh-unix-dev&m=140515171616098&w=2
for more information.
--- configure.ac.orig	2014-12-25 19:09:20.345153528 +0100
+++ configure.ac	2014-12-25 19:10:37.769896808 +0100
@@ -640,10 +640,6 @@ fi
 #l1572 (customized)
 dnl    Checks for library functions. Please keep in alphabetical order
 AC_CHECK_FUNCS([ \
-	arc4random \
-	arc4random_buf \
-	arc4random_stir \
-	arc4random_uniform \
 	asprintf \
 	b64_ntop \
 	__b64_ntop \
@@ -1418,6 +1414,8 @@ AC_ARG_WITH([pam],
 	]
 )
 
+AC_CHECK_FUNCS([arc4random arc4random_buf arc4random_stir arc4random_uniform])
+
 # Check for older PAM
 if test "x$PAM_MSG" = "xyes" ; then
 	# Check PAM strerror arguments (old PAM)
