General cleanup, pt. III.

dist/dist_digest.dist: removes obsolete dist file.
etc/{build.usage,README.md}: updated.
groups/000.host_tools.group:{autoconf,automake,gettext_tiny,install_strip,libtool,m4}_host: moved from groups/010.host_deps.group.
groups/221.native_packages_dev.group:lua: moved from groups/231.native_packages_etc.group.
groups/221.native_packages_dev.group:lua:${PKG_FORCE_AUTORECONF}: set.
groups/231.native_packages_etc.group:{mlogin,tdnf}:${PKG_FORCE_AUTORECONF}: set.
groups/241.native_packages_inet.group:nullmailer:${PKG_FORCE_AUTORECONF}: set.
groups/251.native_packages_lib.group:lib{asr,gpg_error}:${PKG_FORCE_AUTORECONF}: set.
midipix.env, etc/README.md, subr/pkg_configure_autotools.subr: adds FORCE_NO_AUTORECONF.
subr/rtl_fileop.subr: adds ch{mod,own} fileops.
vars/{check_updates,jamvm,lib{asr,gpg_error},lua,mlogin,tdnf}.vars: removes obsolete vars file.

2 files changed, 55 insertions, 19 deletions

diff --git a/etc/README.md b/etc/README.md
index 16392edf..6450625f 100644
--- a/etc/README.md
+++ b/etc/README.md
@@ -43,11 +43,60 @@ or forcibly, respectively:
 ./build.sh [ ... ] -r \*\*mc,zsh
 ```
 
+Restart the ``configure``, ``build``, and ``install`` steps of the ``coreutils`` package.
+```shell
+./build.sh -r coreutils:configure,build,install
+```
+
 Rebuild entire build group:
 ```shell
 ./build.sh [ ... ] -r ALL native_runtime
 ```
 
+## Fault-tolerant & highly optimised 3D laser show-equipped usage screen
+```
+usage: ./build.sh [-a nt32|nt64] [-b debug|release] [-C dir[,..]] [-D kind[,..]] [-F ipv4|ipv6|offline]
+                  [-h] [-p jobs] [-P] [-r [*[*]]ALL|LAST|name[,..][:step,..]] [-R] [-v[v[v[v]]]]
+                  [--as-needed] [--debug-minipix] [<group>[ ..]]
+
+        -a nt32|nt64      Selects 32-bit or 64-bit architecture; defaults to nt64.
+        -b debug|release  Selects debug or release build; defaults to debug.
+        -C dir[,..]       Clean build directory (build,) ${PREFIX} before processing build
+                          scripts (prefix,) source directory (src,) and/or destination directory
+                          (dest) after successful package builds.
+        -D kind[,..]      Produce minimal midipix distribution directory (minipix,) RPM binary
+                          packages (rpm,) and/or deployable distribution ZIP archive (zipdist.)
+                          zipdist implies minipix.
+        -F ipv4|ipv6|offline
+                          Force IPv4 (ipv4) or IPv6 (ipv6) when downloading package archives
+                          and/or Git repositories or don't download either at all (offline.)
+        -h                Show this screen.
+        -p jobs           Enables parallelisation at group-level, whenever applicable.
+        -P                The maximum count of jobs defaults to the number of logical
+                          processors on the host system divided by two (2.)
+                          If -R is not specified and at least one (1) package fails to build,
+                          all remaining package builds will be forcibly aborted for convenience.
+        -r [*[*]]ALL[:step,..]|LAST|name[,..][:step,..]
+                          Restart all packages/the specified comma-separated package(s)
+                          completely or at optionally specified comma-separated step(s)
+                          or restart the last failed package and resume build.
+                          Prepend w/ `*' to automatically include dependencies and `**' to
+                          forcibly rebuild all dependencies.
+
+                          Currently defined steps are:
+                          fetch_wget, fetch_git, fetch_extract,
+                          configure_patch_pre, configure_autotools, configure_patch, configure,
+                          build,
+                          install_subdirs, install_make, install_files, install_libs, install, and install_rpm.
+        -R                Ignore build failures, skip printing package logs, and continue
+                          building (relaxed mode.)
+        -v[v[v[v]]]       Be verbose; -vv: always print package logs; -vvv: set xtrace during package builds; -vvvv: logs fileops.
+        --as-needed       Don't build unless the midipix_build repository has received new commits.
+        --debug-minipix   Don't strip(1) minipix binaries to facilitate debugging minipix.
+        <group>[ ..]      One of: host_deps, host_deps_rpm, host_toolchain, host_tools, minipix,
+                          native_packages, native_runtime, native_toolchain, and/or native_tools.
+```
+
 ## Non-exhaustive list of build variables
 The following variables are primarily defined in ``midipix.env`` and may be overriden
 on a per-build basis on the command-line after the last argument, if any, e.g.:
@@ -109,6 +158,7 @@ and ``URLS_GIT``, respectively.
 | DISABLED                    | Disable package                                                                                                                         |
 | ENV_VARS_EXTRA              | List of double colon-separated environment variable equality sign-separated name-value pairs to set during package build                |
 | FNAME                       | Filename of package archive file                                                                                                        |
+| FORCE_AUTORECONF            | Forcibly run autoreconf -fiv prior to package (GNU autotools or similar) configuration                                                  |
 | GITROOT                     | midipix packages Git URL prefix                                                                                                         |
 | INHERIT_FROM                | Inherit variables from named package                                                                                                    |
 | INSTALL_FILES               | Whitespace-separated list of files to manually install into the package installation destination directory beneath ${PKG_BASE_DIR}      |
diff --git a/etc/build.usage b/etc/build.usage
index da58fcc9..8a2fda19 100644
--- a/etc/build.usage
+++ b/etc/build.usage
@@ -1,23 +1,22 @@
 usage: ./build.sh [-a nt32|nt64] [-b debug|release] [-C dir[,..]] [-D kind[,..]] [-F ipv4|ipv6|offline]
                   [-h] [-p jobs] [-P] [-r [*[*]]ALL|LAST|name[,..][:step,..]] [-R] [-v[v[v[v]]]]
                   [--as-needed] [--debug-minipix] [<group>[ ..]]
+
         -a nt32|nt64      Selects 32-bit or 64-bit architecture; defaults to nt64.
         -b debug|release  Selects debug or release build; defaults to debug.
         -C dir[,..]       Clean build directory (build,) ${PREFIX} before processing build
                           scripts (prefix,) source directory (src,) and/or destination directory
                           (dest) after successful package builds.
-        -D kind[,..]      Produce minimal midipix distribution directory (minipix,) package
-                          tarballs (pkg,) RPM binary packages (rpm,) compressed and optionally
-                          signed binary and source tarballs containing ${PREFIX} sans ${BUILD_WORKDIR}
-                          (t{bz2,gz,xz},) and/or deployable distribution ZIP archive (zipdist.)
-                          {t{bz2,gz,xz},zipdist} imply minipix.
+        -D kind[,..]      Produce minimal midipix distribution directory (minipix,) RPM binary
+                          packages (rpm,) and/or deployable distribution ZIP archive (zipdist.)
+                          zipdist implies minipix.
         -F ipv4|ipv6|offline
                           Force IPv4 (ipv4) or IPv6 (ipv6) when downloading package archives
                           and/or Git repositories or don't download either at all (offline.)
         -h                Show this screen.
         -p jobs           Enables parallelisation at group-level, whenever applicable.
         -P                The maximum count of jobs defaults to the number of logical
-                          processors on the host system.
+                          processors on the host system divided by two (2.)
                           If -R is not specified and at least one (1) package fails to build,
                           all remaining package builds will be forcibly aborted for convenience.
         -r [*[*]]ALL[:step,..]|LAST|name[,..][:step,..]
@@ -39,16 +38,3 @@ usage: ./build.sh [-a nt32|nt64] [-b debug|release] [-C dir[,..]] [-D kind[,..]]
         --debug-minipix   Don't strip(1) minipix binaries to facilitate debugging minipix.
         <group>[ ..]      One of: host_deps, host_deps_rpm, host_toolchain, host_tools, minipix,
                           native_packages, native_runtime, native_toolchain, and/or native_tools.
-
-        ${HOME}/midipix_build.vars, ${HOME}/.midipix_build.vars, and/or ../midipix_build.vars will be sourced if present.
-        If either of ${DEFAULT_GITROOT_HEAD} and/or ${DEFAULT_ZIPDIST_SIGN_GPG_KEY} are to be set, export(1) them there.
-
-        Examples:
-        ./build.sh -r coreutils
-        Completely restart the coreutils build.
-
-        ./build.sh -r coreutils:configure,build,install
-        Restart the configure, build, and install steps of the coreutils build.
-
-        ./build.sh -C prefix -r ALL DEFAULT_GITROOT_HEAD=...
-        Clean ${PREFIX} and forcibly rebuild everything.