improve --help for --main-stacksize and supported ARM cpu
If the command line option --main-stacksize is not used,
the current ulimit value is used, with a min of 1MB
and a max of 16MB. Document this min/max default formula
in the --help.

Also indicate that Valgrind supports ARMv7


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13426 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/none/tests/cmdline1.stdout.exp b/none/tests/cmdline1.stdout.exp
index ed662fb..4ba4633 100644
--- a/none/tests/cmdline1.stdout.exp
+++ b/none/tests/cmdline1.stdout.exp
@@ -47,7 +47,7 @@
     --max-stackframe=<number> assume stack switch for SP changes larger
                               than <number> bytes [2000000]
     --main-stacksize=<number> set size of main thread's stack (in bytes)
-                              [use current 'ulimit' value]
+                              [min(max(current 'ulimit' value,1MB),16MB)]
 
   user options for Valgrind tools that replace malloc:
     --alignment=<number>      set minimum alignment of heap allocations [not used by this tool]