tweak several #includes of settings.h to include types.h instead (all of these are for clarity, as types.h is indirectly included by later #includes), and add #include <wolfssl/wolfcrypt/types.h> where missing;
remove trailing semicolons from PRAGMA*() macro invocations as they are unneeded and can be harmful (inducing frivolous -Wdeclaration-after-statement etc.).
linuxkm/linuxkm_wc_port.h: activate SAVE/RESTORE_VECTOR_REGISTERS() whenever defined(WOLFSSL_LINUXKM_USE_SAVE_VECTOR_REGISTERS) for benchmark.c support, independent of vector crypto features;
fix and optimize various alignment issues with stack and heap allocations;
fix macro definitions for XMALLOC/XREALLOC/XFREE to correctly use kvmalloc and friends when defined(HAVE_KVMALLOC), and to use wolfSSL_Malloc() and friends when defined(WOLFSSL_TRACK_MEMORY);
purge stale LINUXKM_SIMD_IRQ code.
linuxkm: when -DWOLFCRYPT_ONLY, don't include ssl.h in module_exports.c.template and module_hooks.c, and fix gating to work right with that;
wolfssl/wolfcrypt/types.h: add support for a WOLFSSL_XFREE_NO_NULLNESS_CHECK gate (used in cppcheck analysis).
smallstack refactors for wolfcrypt/src/rsa.c:wc_CheckProbablePrime_ex() and wolfcrypt/src/pwdbased.c:wc_PKCS12_PBKDF_ex();
add WARN_UNUSED_RESULT macro to types.h;
text format cleanup;
fix internal.c:LowResTimer() implementation.
refactor tls13.c:TimeNowInMilliseconds() for kernel 4.9 and 3.16 compat.
use ktime_get_coarse_real_ts64() only for kernel 5.x+. in kernel 4.x, use its older form, current_kernel_time64(), and in 3.x, use getnstimeofday().
linuxkm/module_hooks.c: fix wolfssl_init() pie code to be compatible with kernel 4.4-;
fix allocate_wolfcrypt_irq_fpu_states() return codes to all be wolfcrypt codes, and in calling code, pass up that code (suggested by dgarske peer review).
add build-time support for module signing using native Linux facility;
add support for alternative licenses using WOLFSSL_LICENSE macro;
improve load-time kernel log messages;
add support for sp-math-all asm/AVX2 acceleration;
add error-checking and return in SAVE_VECTOR_REGISTERS();
implement support for x86 accelerated crypto from interrupt handlers, gated on WOLFSSL_LINUXKM_SIMD_X86_IRQ_ALLOWED:
* wolfcrypt_irq_fpu_states
* am_in_hard_interrupt_handler()
* allocate_wolfcrypt_irq_fpu_states()
* free_wolfcrypt_irq_fpu_states()
* save_vector_registers_x86()
* restore_vector_registers_x86()
add WOLFSSL_LINUXKM_SIMD, WOLFSSL_LINUXKM_SIMD_X86, and WOLFSSL_LINUXKM_SIMD_ARM macros for more readable gating.
* Adds `--enable-linuxkm-pie` and associated infrastructure, to support FIPS mode in the Linux kernel module.
* Adds `tests/api.c` missing (void) arglist to `test_SSL_CIPHER_get_xxx()`.
