update to memcached-1.6.42, ok giovanni

various security related fixes in
https://github.com/memcached/memcached/wiki/ReleaseNotes1642

others:
https://github.com/memcached/memcached/wiki/ReleaseNotes1641
https://github.com/memcached/memcached/wiki/ReleaseNotes1640

misc/memcached/Makefile

@@ -1,6 +1,6 @@
 COMMENT=	distributed memory object caching system
 
-DISTNAME=	memcached-1.6.39
+DISTNAME=	memcached-1.6.42
 CATEGORIES=	misc
 
 # https://github.com/memcached/memcached

misc/memcached/distinfo

@@ -1,2 +1,2 @@
-SHA256 (memcached-1.6.39.tar.gz) = I+VQfpM7FUYxYdTF05IbDF80C1Qtbt1/bF4Xw08Ro2M=
-SIZE (memcached-1.6.39.tar.gz) = 1284104
+SHA256 (memcached-1.6.42.tar.gz) = UPCLh51PnTbeqdkF6eqt4Vxwjjjbfppz/CHci0U5Xec=
+SIZE (memcached-1.6.42.tar.gz) = 1270958

misc/memcached/patches/patch-doc_Makefile

@@ -9,4 +9,4 @@ Index: doc/Makefile
 +LIBS = -levent_core
  LTLIBOBJS = 
  MAKEINFO = ${SHELL} '/home/dormando/p/code/memcached/missing' makeinfo
- MKDIR_P = /usr/bin/mkdir -p
+ MKDIR_P = mkdir -p

misc/memcached/patches/patch-memcached_c

@@ -1,7 +1,7 @@
 Index: memcached.c
 --- memcached.c.orig
 +++ memcached.c
-@@ -5546,8 +5546,8 @@ int main (int argc, char **argv) {
+@@ -5554,8 +5554,8 @@ int main (int argc, char **argv) {
                  start_lru_maintainer = false;
                  break;
              case NO_DROP_PRIVILEGES: