Adjust cStrCHR() and cStrASC() to use 64bit values
Adjust cv*/mk* functions to use INTEGER=ssize_t and LONG=int
utf_conv.bi: Turn enum params into a LONG, to match 64bit rtlib

(in C, enums become ints, and int stays 32bit on 64bit)
Adjust struct packing for 64bit

According to
	http://en.wikipedia.org/wiki/Data_structure_alignment

the only difference between 64bit and 32bit is that 8-byte types (double,
long long) are now really 8-byte aligned everywhere, not just on Windows,
and of course pointers also are 8-byte aligned.
Fix varargs promotion to 32bit int
Fix 32bit assumption in hFloatToHex()
Fix hCheckFileFormat() to hopefully not break on 64bit

- Always read 4 bytes, not depending the data type of BOM variable
- Change BOM variable to be a 32bit LONG instead of INTEGER
  (signed, so comparisons like <if( BOM = &hFFFE0000 ) then> should keep
   working even if the operands will be promoted to signed 64bit)
Remove x86 assumption comment from hInitVptr(), doesn't seem to be

since it's using env.pointersize, which is good as it will be remapped
depending on 32bit/64bit, and nothing else seems to be wrong.
Don't worry about returning structs in registers

hGetReturnType() won't do it for -gen gcc anyways. We'd only have to take
care if we had our own x86_64 -gen gas backend.