Install the TkG configuration used to the system (#49)

* linux-tkg: Install configuration used.

* linux-tkg: Document the installed config file.

linux58-tkg/PKGBUILD

@@ -50,7 +50,7 @@ url="http://www.kernel.org/"
 license=('GPL2')
 makedepends=('xmlto' 'docbook-xsl' 'kmod' 'inetutils' 'bc' 'libelf' 'pahole' 'patchutils' 'flex' 'python-sphinx' 'python-sphinx_rtd_theme' 'graphviz' 'imagemagick' 'git')
 optdepends=('schedtool')
-options=('!strip')
+options=('!strip' 'docs')
 source=("https://www.kernel.org/pub/linux/kernel/v5.x/linux-${_basekernel}.tar.xz"
         "https://www.kernel.org/pub/linux/kernel/v5.x/patch-${pkgver}.xz"
         "https://raw.githubusercontent.com/graysky2/kernel_gcc_patch/master/enable_additional_cpu_optimizations_for_gcc_v10.1%2B_kernel_v5.8%2B.patch"
@@ -137,6 +137,9 @@ build() {
     msg2 'ccache was found and will be used'
   fi
 
+  # document the TkG variables, excluding "_", "_EXT_CONFIG_PATH", and "_where".
+  declare -p | cut -d ' ' -f 3 | grep -P '^_(?!=|EXT_CONFIG_PATH|where)' > "${srcdir}/customization-full.cfg"
+
   # build!
   _runtime=$( time ( schedtool -B -n 1 -e ionice -n 1 make ${_force_all_threads} LOCALVERSION= bzImage modules 2>&1 ) 3>&1 1>&2 2>&3 ) || _runtime=$( time ( make ${_force_all_threads} LOCALVERSION= bzImage modules 2>&1 ) 3>&1 1>&2 2>&3 )
 }
@@ -178,6 +181,9 @@ hackbase() {
   sed -e "s|cleanup|${pkgbase}-cleanup|g" "${srcdir}"/90-cleanup.hook |
     install -Dm644 /dev/stdin "${pkgdir}/usr/share/libalpm/hooks/90-${pkgbase}.hook"
   install -Dm755 "${srcdir}"/cleanup "${pkgdir}/usr/share/libalpm/scripts/${pkgbase}-cleanup"
+
+  # install customization file, for reference
+  install -Dm644 "${srcdir}"/customization-full.cfg "${pkgdir}/usr/share/doc/${pkgbase}/customization.cfg"
 }
 
 hackheaders() {