[patch, fortran] Fix PR 35719

[Thomas Koenig]

Hello world,

the bug, discovered by Dick Hendrickson, was caused by using a null
pointer as return value when trying to malloc 0 bytes.  This caused the
ASSOCIATED function to fail when applied to a pointer to an automatic
array.  The approach in this patch is to allocate at least one byte
for each malloc, so the comparison of the pointers can be meaningful.

Regression-tested on i686-pc-linux-gnu.  OK for trunk?

	Thomas

2008-05-07  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/35719
	* trans.c (gfc_call_malloc): If size equals zero, allocate one
	byte; don't return a null pointer.

2008-05-07  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/35719
	* gfortran.dg/associated_5.f90:  New test.

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