Stack overflow under Windows and crash under MacOSX in intersection with arithmetic expansions

[BrunoLevy]

Crash under Windows and MacOS with:

   intersect geogram.data/Intersections/rot_seven_cubes.obj remove_internal_shells=true

Windows and MacOSX have smaller stacks than Linux:

• Linux: 10 Mb
• Windows: 1Mb
• MacOSX: 512K

expansion and expansion_nt make a massive usage of the stack (to represent intermediate computations). It is OK for standard predicates, but not for creating new points with exact coordinates.

[BrunoLevy]

• Added GEO_HAS_BIG_STACK macro in basic/memory.h, only defined under Linux
• Optimized specializations of some functions in numerics/exact_geometry.h and numerics/expansion_nt.h are only activated if GEO_HAS_BIG_STACK is defined (else the defaut implementation that allocates expansions on heap is used)
• In the implementation of expansion product in numerics/multi_precision.cpp, now allocates temporaries on heap if length is larger than a certain threshold (1024 components).

Note:

• allocating expansions on heap rather than on stack has a cost. intersect PR12_ter remove_internal_shells=true takes 322 seconds with expansions on heap (GEO_HAS_BIG_STACK undefined) rather than 112 seconds
• if need be, could be probably accelerated by de-recursiving expansion_product() and doing a single allocation for all subterms.