component/userhosts: use github.com/figiel/hosts for compatibility with recent libc

In ubuntu 21.04 (libc6 2.33-0ubuntu5) or current debian testing
(libc6 2.32-5) no longer use open to open /etc/hosts, but what appears
as "openat" in strace output - but can not be replaced by defining an
openat function.

This uses https://github.com/figiel/hosts which uses another approach
of replacing getaddrinfo, gethostbyname* and inet_aton.

Users have been updated a bit, because there are some small differences:
 - the /etc/hosts replacement file is defined by HOSTS_FILE environment
   variable, not HOSTS
 - the library name is libuserhosts.so, not userhosts.so

Other notable differences, for which we did not need code change are:
 - the new library also try to load a file when HOSTS_FILE is not set
 - the new library still use original /etc/hosts file
 - the new library supports aliases to hostnames, not only ip addresses

component/userhosts/buildout.cfg

 [userhosts]
 recipe = slapos.recipe.cmmi
 shared = true
-url = https://lab.nexedi.com/nexedi/userhosts/repository/${:revision}/archive.tar.gz
-revision = a05fe5a3a5cb7005351ef4ec41460089f3ce4d0a
-md5sum = 5a80b4d962d975f290a60cf790c3334d
+url = https://github.com/figiel/hosts/archive/${:revision}.tar.gz
+revision = fdb45fe219593d63453f4be55cfc2a1199c18f59
+md5sum = 9ff5407132a2a67200ef1036a02f0ee2
 configure-command = true
 make-options = PREFIX=@@LOCATION@@
-make-targets = check install
+make-targets = test install

software/slapos-testing/buildout.hash.cfg

@@ -15,4 +15,4 @@
 
 [template]
 filename = instance.cfg
-md5sum = 597c29546519aabe7259e416d0b92095
+md5sum = ba6c572678687081ce111d3805be3cee

software/slapos-testing/instance.cfg

@@ -35,10 +35,10 @@ repository = ${caucase-repository:location}
 [caucase-test-runner]
 recipe = slapos.recipe.template:jinja2
 template = inline:#!/bin/sh
-  export HOSTS="$(mktemp)"
-  trap 'rm "$HOSTS"' EXIT
-  printf '%s testhost\n%s testhost\n' "$SLAPOS_TEST_IPV4" "$SLAPOS_TEST_IPV6" > "$HOSTS"
-  export CAUCASE_NETLOC=testhost:8000 LD_PRELOAD=${userhosts:location}/lib/userhosts.so:$LD_PRELOAD
+  export HOSTS_FILE="$(mktemp)"
+  trap 'rm "$HOSTS_FILE"' EXIT
+  printf '%s testhost\n%s testhost\n' "$SLAPOS_TEST_IPV4" "$SLAPOS_TEST_IPV6" > "$HOSTS_FILE"
+  export CAUCASE_NETLOC=testhost:8000 LD_PRELOAD=${userhosts:location}/lib/libuserhosts.so:$LD_PRELOAD
   exec python -m unittest discover -v
 rendered = $${caucase:location}/host_setting.sh
 

stack/erp5/buildout.hash.cfg

@@ -70,7 +70,7 @@ md5sum = 7a14019abf48ca100eb94d9add20f5ae
 
 [template]
 filename = instance.cfg.in
-md5sum = bbef65b4edeb342f08309604ca3717d5
+md5sum = 0444d646607f8643e987bb62d1cbbc1d
 
 [template-erp5]
 filename = instance-erp5.cfg.in
@@ -86,7 +86,7 @@ md5sum = bc821f9f9696953b10a03ad7b59a1936
 
 [template-zope]
 filename = instance-zope.cfg.in
-md5sum = f3121380ab4d31ba5f4984aec74d0a2f
+md5sum = 09895deebca3206425fada3caf1d92cf
 
 [template-balancer]
 filename = instance-balancer.cfg.in

stack/erp5/instance-zope.cfg.in

@@ -185,7 +185,7 @@ context = key host_dict hosts-parameter:host-dict
 recipe = slapos.recipe.template:jinja2
 mode = 755
 template = inline:#!{{ parameter_dict['dash'] }}/bin/dash
-  export HOSTS=${hosts:rendered}
+  export HOSTS_FILE=${hosts:rendered}
   export LD_PRELOAD={{ parameter_dict['userhosts'] }}:$LD_PRELOAD
   exec "$@"
 rendered = ${directory:bin}/userhosts

stack/erp5/instance.cfg.in

@@ -110,7 +110,7 @@ link-binary = {{ dumps(zope_link_binary) }}
 fonts = {{ dumps(zope_fonts) }}
 fontconfig-includes = {{ dumps(zope_fontconfig_includes) }}
 template-fonts-conf = {{ dumps(template_fonts_conf) }}
-userhosts = {{ userhosts_location }}/lib/userhosts.so
+userhosts = {{ userhosts_location }}/lib/libuserhosts.so
 site-zcml = {{ site_zcml }}
 extra-path-list = {{ dumps(extra_path_list) }}
 matplotlibrc = {{ matplotlibrc_location }}