w3m: do not always link to RAND_egd for openssl

This fixes the build for libressl >= 2.3 as RAND_egd has been removed as
it is insecure.

pkgs/applications/networking/browsers/w3m/RAND_egd.libressl.patch

@@ -0,0 +1,11 @@
+--- a/url.c  2014-07-14 12:31:30.476563116 +0200
++++ b/url.c   2014-07-14 12:32:16.364918248 +0200
+@@ -268,7 +268,7 @@ init_PRNG()
+     if (RAND_status())
+ 	return;
+     if ((file = RAND_file_name(buffer, sizeof(buffer)))) {
+-#ifdef USE_EGD
++#if defined(USE_EGD) && defined(HAVE_SSL_RAND_EGD)
+ 	if (RAND_egd(file) > 0)
+ 	    return;
+ #endif

pkgs/applications/networking/browsers/w3m/default.nix

@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
 
   NIX_LDFLAGS = stdenv.lib.optionalString stdenv.isSunOS "-lsocket -lnsl";
 
-  patches = [ ./glibc214.patch ]
+  patches = [ ./glibc214.patch ./RAND_egd.libressl.patch ]
     # Patch for the newer unstable boehm-gc 7.2alpha. Not all platforms use that
     # alpha. At the time of writing this, boehm-gc-7.1 is the last stable.
     ++ optional (boehmgc.name != "boehm-gc-7.1") [ ./newgc.patch ]