Implement support for x86 macOS (i386)

[ciciplusplus]

Checklist

Which kind of PR do you create?

• This PR only contains minor fixes.
• This PR contains major feature update.
• This PR introduces a new function/api for Qiling Framework.

Coding convention?

• The new code conforms to Qiling Framework naming convention.
• The imports are arranged properly.
• Essential comments are added.
• The reference of the new code is pointed out.

Extra tests?

• No extra tests are needed for this PR.
• I have added enough tests for this PR.
• Tests will be added after some discussion and review.

Changelog?

• This PR doesn't need to update Changelog.
• Changelog will be updated after some proper review.
• Changelog has been updated in my PR.

Target branch?

• The target branch is dev branch.

One last thing

• I have read the contribution guide

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Known issues

• qtool was changed to add /dev/urandom fs mapping. Probably it should be another cli option to define a list of guest to host fs mapping
• ql_syscall_thread_fast_set_cthread_self implementation for x86 is probably incorrect (i just copied 64 variant)
• posix open flags for arm64 host were copied from x8664 host. (maybe better to use this instead)
• Some functions which are suppose to reside in commpage implemented with jump call to my_ prefixed host functions. Could be not the cleanest solution, open to refactoring suggestions/other approaches.

Additional fixes

Below fixes are not necessary related to x86 support and could be merged separately if preferred:

• GDB now supported on macOS host
• Fix for GDB instructions step and stepi (which both previously make emu_state STOPPED)
• Fix ql_syscall_write_nocancel to return number of bytes written
• Fix ql_syscall_pread
• Replace mmap2 with mmap on macOS

Dependencies

rootfs/x86_macos should have following files:

Linker

• /usr/lib/dyld

Dylibs

• /usr/lib/libgcc_s.1.dylib
• /usr/lib/libSystem.B.dylib
• /usr/lib/system/libmathCommon.A.dylib

Run example

% ./qltool run -f examples/rootfs/x86_macos/bin/x86_hello --rootfs examples/rootfs/x86_macos --verbose off
Hello, World!