scripts: add sed expression to apply when renumbering patches

Some patchsets have superfluous members in their names (eg. the ones coming
from Gentoo), so it can come in handy to pass a sed RE to strip them out of
the final patch name.
Also add a 'fake' mode, where the command will only be printed and not
executed, so we can check beforehand if the rename will be OK.

scripts/patch-renumber.sh

@@ -9,33 +9,45 @@ myname="$0"
 
 doUsage() {
   cat <<_EOF_
-Usage: ${myname} <dir> <base> <inc>
-    Will renumber all patches found in <dir>, starting at <base>, and with
-    an increment of <inc>
-    Eg.: patch-renumber patches/gcc/4.3.1 100 10
+Usage: ${myname} <dir> <base> <inc> [sed_re]
+    Will renumber all patches found in 'dir', starting at 'base', and with
+    an increment of 'inc'.
+    If 'sed_re' is given, it is interpreted as a valid sed expression, and
+    it will be applied to the patch name.
+    If the environment variable FAKE is set to 'y', then the command will
+    only be printed, and not executed (so you can check beforehand).
+    Eg.:
+      patch-renumber.sh patches/gcc/4.3.1 100 10
+      patch-renumber.sh patches/gcc/4.2.4 100 10 's/(all[_-])*(gcc[-_])*//;'
 _EOF_
 }
 
-[ $# -eq 3 ] || { doUsage; exit 1; }
+[ $# -lt 3 -o $# -gt 4 ] && { doUsage; exit 1; }
 [ -d "${1}" ] || { doUsage; exit 1; }
 
 dir="${1}"
 cpt="${2}"
 inc="${3}"
+sed_re="${4}"
 
 case "$(LC_ALL=C hg id "${dir}" 2>/dev/null)" in
-    "") CMD="mv -v";;
-    *)  CMD="hg mv";;
+    "") CMD="";;
+    *)  CMD="hg";;
 esac
 
-for p in "${dir}"/*.patch; do
+if [ "${FAKE}" = "y" ]; then
+    CMD="echo ${CMD}"
+fi
+
+for p in "${dir}"/*.patch*; do
     [ -e "${p}" ] || { echo "No such file '${p}'"; exit 1; }
-    newname="$(printf "%03d-%s"                                 \
-                      "${cpt}"                                  \
-                      "$(basename "${p}"                        \
-                        |"${sed}" -r -e 's/^[[:digit:]]+[-_]//' \
-                       )"                                       \
+    newname="$(printf "%03d-%s"                                     \
+                      "${cpt}"                                      \
+                      "$( basename "${p}"                           \
+                          |"${sed}" -r -e 's/^[[:digit:]]+[-_]//'   \
+                                       -e "${sed_re}"               \
+                        )"                                          \
               )"
-    [ "${p}" = "${dir}/${newname}" ] || ${CMD} "${p}" "${dir}/${newname}"
+    [ "${p}" = "${dir}/${newname}" ] || ${CMD} mv -v "${p}" "${dir}/${newname}"
     cpt=$((cpt+inc))
 done