Add HAVE_GETPID to options.h if getpid detected

[cconlon]

Description

PR #8867 added use of getpid(), and also adjusted the definition of WC_RNG in wolfssl/wolfcrypt/random.h based on HAVE_PID:

#if defined(HAVE_GETPID) && !defined(WOLFSSL_NO_GETPID)
    pid_t pid;
#endif

The HAVE_GETPID define was not being stored to wolfssl/options.h, so applications depending on the sizeof(WC_RNG) would have gotten a different structure size.

This PR modifies configure.ac to define HAVE_GETPID in wolfssl/options.h if getpid() is detected.

Testing

Existing unit tests, and wolfcrypt-jni test cases.

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[cconlon]

Retest this please Jenkins

[JacobBarthelmeh]

Retest this please Jenkins. Made a change now for PRB-fips-ready-config to account for HAVE_GETPID macro define when creating the user_settings.h file to test with.

[dgarske]

We need this PR merged. Worked with Aidan to debug an issue with wolfProvider that turned out to be the same WC_RNG size issue corrupting memory due to struct size mismatch. Multiple engineers have each wasted multi hours because of this change.

[dgarske]

Merging before prb master finishes. Thank you Chris and Jacob