syscall_emul: remove mmapFlagTable

After all this it turns out we don't even use it.

syscall_emul: factor out flag tables into common file

The openFlagTable and mmapFlagTables for emulated Linux
platforms are basically identical, but are specified
repetitively for every platform. Use a common file
that gets included for each platform so that we only
have one copy, making them more consistent and simplifying
changes (like adding #ifdefs).

In the process, made some minor fixes that slipped through
due to previous inconsistencies, and added more #ifdefs
to try to fix building on alternative hosts.

syscall_emul: extend mmap system call to support file backed mmaps

For O3, which has a stat that counts reg reads, there is an additional
reg read per mmap() call since there's an arg we no longer ignore.
Otherwise, stats should not be affected.

syscall_emul: add many Linux kernel flags

syscall_emul: rename OpenFlagTransTable struct

The structure definition only had the open system call flag set in mind when
it was named, so we rename it here with the intention of using it to define
additional tables to translate flags for other system calls in the future.

style: remove trailing whitespace

Result of running 'hg m5style --skip-all --fix-white -a'.

mips: Fix RLIMIT_RSS naming

MIPS defined RLIMIT_RSS in a way that could cause a naming conflict with
RLIMIT_RSS from the host system. Broke clang+MacOS build.

syscall emulation: Enabled getrlimit and getrusage for x86.
Added/moved rlimit constants to base linux header file.

This patch is a revised version of Vince Weaver's earlier patch.

syscall emulation: Clean up ioctl handling, and implement for x86.

Enable different whitelists for different OS/arch combinations,
since some use the generic Linux definitions only, and others
use definitions inherited from earlier Unix flavors on those
architectures.

Also update x86 function pointers so ioctl is no longer
unimplemented on that platform.

This patch is a revised version of Vince Weaver's earlier patch.

syscall_emul: implement MAP_FIXED option to mmap()

syscall: Addition of an ioctl command code for Power.

Syscalls: Implement sysinfo() syscall.

MIPS: Many style fixes.
White space, commented out code, some other minor fixes.

Get rid of 'using namespace' declarations in headers.

syscall: Expose ioctl for MIPS

style: Remove non-leading tabs everywhere they shouldn't be. Developers should configure their editors to not insert tabs

fix MIPS headers

Add in files from merge-bare-iron, get them compiling in FS and SE mode

mips import pt. 1

src/arch/mips/SConscript:
"mips import pt.1".

Don't use the exact same name as a system header #define

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.