scripts: misc help and auto-complete fixes

- don't list samples in the main help screen
- improve the samples listing in list-samples
- don't document the 'config' action, it's long dead
- document the 'V' environment variable
- improve on START, STOP and PREFIX environment variables
- add PREFIX and V to autocomplete
- advertise auto-complete at install time

--- binutils/ld/emulparams/elf_i386.sh

+++ binutils/ld/emulparams/elf_i386.sh

@@ -13,3 +13,13 @@

 NO_SMALL_DATA=yes

 SEPARATE_GOTPLT=12

 IREL_IN_PLT=

+

+# In Gentoo, we install 32bit libs into /lib32 in an

+# ABI setup with amd64/x86

+case "$target" in

+  x86_64*-linux*)

+    case "$EMULATION_NAME" in

+      *i386*) LIBPATH_SUFFIX=32  ;;

+    esac

+  ;;

+esac