etc/{build.usage,README.md}: updated.

1 files changed, 35 insertions, 26 deletions

diff --git a/etc/build.usage b/etc/build.usage
index 6bd08921..0f0f816c 100644
--- a/etc/build.usage
+++ b/etc/build.usage
@@ -1,41 +1,50 @@
-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>[ ..]]
+usage: ./build.sh [-a nt32|nt64]  [-b debug|release] [-C dir[,..]] [-D kind[,..]]
+                  [-F ipv4|ipv6|offline]   [-h]   [-p jobs]   [-P]  [-r ALL|LAST]
+                  [-r [*[*]]name[,..][:step,..]] [-R] [-v[v[v[v]]]] [--as-needed]
+                  [--debug-minipix] [<group>|<variable name>=<variable override>[ ..]]
 
         -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.
+                          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.)
+                          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.
+
+                          If -R is not specified and at least one (1) package fails to
+                          build, all remaining package builds will be forcibly aborted.
+
+        -r ALL|LAST       Restart all packages or the last failed package and resume
+                          build, resp.
+        -r [*[*]]name[,..][:step,..]
+                          Restart the specified comma-separated package(s) completely or
+                          at optionally specified comma-separated list of build steps.
+
                           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.
+                          Currently defined build 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.
+        -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: dev_packages, dist, host_deps, host_deps_rpm, host_toolchain,
-                          host_tools, minipix, native_packages, native_runtime, native_toolchain,
-                          native_tools.
+        <group>[ ..]      One of: dev_packages, dist, host_deps, host_deps_rpm,
+                          host_toolchain, host_tools, minipix, native_packages, 
+                          native_runtime, native_toolchain, native_tools.