retain a minimal "methods" struct in the mctx

- this enables memory to be allocated and freed in dyndb modules
  when named is linked statically. when we standardize on libtool,
  this should become unnecessary.
- also, simplified the isc_mem_create/createx API by removing
  extra compatibility functions
26 jobs for 479-remove-isc_bind9 in 8 minutes and 40 seconds (queued for 14 seconds)
Status Job ID Name Coverage
  Precheck
passed #68730
linux docker amd64
precheck:debian:sid:amd64

00:00:17

 
  Build
passed #68731
linux docker amd64
build:centos:centos6:amd64

00:03:02

passed #68732
linux docker amd64
build:centos:centos7:amd64

00:03:12

passed #68733
linux docker amd64
build:clang:debian:stretch:amd64

00:02:21

passed #68737
linux docker i386
build:clang:debian:stretch:i386

00:02:24

passed #68734
linux docker amd64
build:debian:jessie:amd64

00:03:09

passed #68736
linux docker amd64
build:debian:sid:amd64

00:03:32

passed #68738
linux docker i386
build:debian:sid:i386

00:02:20

passed #68735
linux docker amd64
build:debian:stretch:amd64

00:02:15

passed #68739
linux docker amd64
pkcs11:build:debian:sid:amd64

00:01:51

 
  Test
passed #68753
linux docker amd64
install:debian:sid:amd64

00:02:11

passed #68755
linux docker amd64
pkcs11:systemtest:debian:sid:amd64

00:04:39

passed #68754
linux docker amd64
pkcs11:unittest:debian:sid:amd64

00:00:47

passed #68747
linux docker amd64
systemtest:centos:centos6:amd64

00:04:46

passed #68748
linux docker amd64
systemtest:centos:centos7:amd64

00:04:37

passed #68749
linux docker amd64
systemtest:debian:jessie:amd64

00:04:48

passed #68751
linux docker amd64
systemtest:debian:sid:amd64

00:04:40

passed #68752
linux docker i386
systemtest:debian:sid:i386

00:04:44

passed #68750
linux docker amd64
systemtest:debian:stretch:amd64

00:04:48

passed #68740
linux docker amd64
unittest:centos:centos6:amd64

00:00:52

passed #68741
linux docker amd64
unittest:centos:centos7:amd64

00:00:53

passed #68745
linux docker amd64
unittest:clang:debian:stretch:amd64

00:00:41

passed #68742
linux docker amd64
unittest:debian:jessie:amd64

00:00:46

passed #68744
linux docker amd64
unittest:debian:sid:amd64

00:00:45

passed #68746
linux docker i386
unittest:debian:sid:i386

00:00:50

passed #68743
linux docker amd64
unittest:debian:stretch:amd64

00:00:54