Fix bool typedef slirp glue

[OpenPosixDev]

This PR fixes a bug in slirp_glue/config-host.h where the bool type was not correctly defined in environments using C versions prior to C23 (e.g., C99 or C11). The typedef for bool is only defined as int when the C version is lower than C23. Starting with C23, bool is automatically supported, so this typedef is only provided for older C versions.

Changes:

• Added: Conditional definition of bool as int for C versions lower than C23.
• No functional changes for C23 or newer versions.
• These changes ensure compatibility with older C versions and avoid conflicts with bool in C23 and later.

Testing:

• This change has been tested on systems using C99 and C11 to ensure that the bool type is correctly defined.
• No changes in behavior when using C23 or higher.

Additional Notes:

• This change is backward-compatible and should not interfere with existing implementations.

[rbanffy]

Did the issue appear to you with the make build process or only with cmake? The former is passing the --std=c99 option to the compiler. The issue seems to be that the cmake workflow isn't passing it.

[OpenPosixDev]

Thanks for the fast reply! The problem only occurs with CMake, as it's not passing the --std=c99 flag to the compiler. The fix works fine for me, but the CMake workflow could definitely be improved if needed.

[rbanffy]

I believe that's the right way to solve this issue, but my knowledge of cmake is not the best.

[OpenPosixDev]

Same for me.

[bscottm]

@OpenPosixDev: While passing the "-std=c99" flag might fix the problem in the short term, but take a deeper look at the slirp code base in open-simh. It's a very hacky adaptation from the QEMU code base from around 8 years ago. All of the types are fixed in place where a configure would otherwise have provided the proper platform definition (among other things.)

If you could, try the commit in PR #485 where some of your proposed fixes might already be addressed. Might not specifically address the slirp code base (been a couple of weeks since I looked at it.) Might be a better place to merge fixes.