Add example use with autotools

[BrianSipos]

Related to guide updates for NASA-AMMOS/BSL-docs#38.

Part of this update cleans up the public interface of BSL to avoid leaking internal implementation details.

[BrianSipos]

@250MHz it was discovered that because the BSL public interface uses struct timespec its API requires a minimum POSIX version on the user compiling side. This change adds a corresponding define to the pkg-config control for bsl. Does this seem reasonable for your use? Any alternative would need manual user config of the compiler to be compatible, but would allow for other compatibility.

[250MHz]

@250MHz it was discovered that because the BSL public interface uses struct timespec its API requires a minimum POSIX version on the user compiling side. This change adds a corresponding define to the pkg-config control for bsl. Does this seem reasonable for your use? Any alternative would need manual user config of the compiler to be compatible, but would allow for other compatibility.

I think ION uses the same _POSIX_C_SOURCE as BSL and the macro is currently available in all our files (ION does this incorrectly, IMO), so it wouldn't affect us, but I'm not sure if putting feature test macros into the .pc's Cflags is desirable. I'd have to look more into how other libraries handle feature test macros.

But does struct timespec only appear in public headers at

BSL/src/bsl/BPSecLib_Public.h

Lines 456 to 457 in 7dc5be1

	void (*log_event)(const struct timespec *timestamp, int severity, const char *filename, int lineno,
	const char *funcname, const char *format, va_list args);

and

BSL/src/bsl/mock_bpa/log.h

Lines 70 to 71 in 7dc5be1

	void mock_bpa_LogEvent(const struct timespec *timestamp, int severity, const char *filename, int lineno,
	const char *funcname, const char *format, va_list args);

If so, does struct timespec even need to be defined since these are pointers? Can we just forward declare struct timespec and not have to worry about feature test macros?

[BrianSipos]

That is true and simplifies configuration. I will update to forward declare this and add an explanation in the product guide.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[mfarina1]

Approving this now so that once Brian does the forward declare update, he can merge the PR