Semihosting fix

[Schwarz, Konrad]

> -----Original Message-----
> From: newlib-owner@sourceware.org [mailto:newlib-owner@sourceware.org]
> On Behalf Of David Hoover
> Sent: Tuesday, April 19, 2016 3:54 PM
> To: newlib@sourceware.org
> Subject: Semihosting fix

> More often than not, dynamic stack and heap information is not
> available, and the system call generally provides null values in this
> case. Segger GDBServer and OpenOCD 0.9.9 are examples of this.

Not to criticize your patch, but Segger GDBServer and OpenOCD are
deficient in this regard.  I hope you have notified them.
Lauterbach, for example, provides a way of setting this
information from the user interface.

In most cases, the memory layout is known at link time.
Ideally, it would be possible to set the heap and stack
limits at link time, so that if this information is
not provided by the debugger, the default values
set by the linker would be used.