libpthread: Test pthread_create link errors without -(l)pthread.

Prompted by:

PR lib/59685: libcrypto should not depend on libpthread

branches: 1.9.2;
tests/usr.bin/cc: Add test for ctype(3) detection.

PR lib/58912: ctype(3) abuse detection fails for variable references

branches: 1.8.10;
Add ATF c and c++ tests for TSan, MSan, libFuzzer

These tests require Clang/LLVM 7 or newer on NetBSD.

Contributed by Yang Zheng during GSoC 2018.

branches: 1.7.2;
add very simple test that you can link -fopenmp.

currently fails, but should work soon...

Move common UBSAN test case code into ubsan_common.subr

Reviewed by <kamil>

Move common ASAN test case code into asan_common.subr

Reviewed by <kamil>

branches: 1.4.2;
Add new ATF Undefined Behavior Sanitizer tests

Add new cc and c++ tests to check whether UBSan works.
These tests are prepared for GCC (in base) and Clang (with external patches).

Enable these tests for all ports by default, just verify whether we are
using GCC/Clang or a compatible compiler.

Add five equivalent C and C++ tests:
- Integer addition overflow
- Integer divide by zero
- Integer negation overflow
- Integer subtraction overflow
- VLA out of bounds

All tests pass on NetBSD/amd64.

Patch submitted by <Harry Pantazis>
Minor cleanup by <myself>

Import new C and C++ ATF tests for ASan

Add new tests:
- tests/usr.bin/cc/t_asan_poison.sh
- tests/usr.bin/c++/t_asan_poison.sh

These tests verify the following build options:
- regular
- profile
- pic
- pie
- compat32
- (static unsupported)

These tests verify whether ASan code can include compiler and sanitizer
specific header: <sanitizer/asan_interface.h>. The testing code checks
the ASAN_POISON_MEMORY_REGION() functionality, poisoning valid memory and
asserting that it triggers expected failure.

Patch submitted by <Siddharth Muralee>

Add new ATF tests for Address Sanitzier (ASan)

Add new C and C++ tests:
- t_asan_double_free
- t_asan_global_buffer_overflow
- t_asan_heap_overflow
- t_asan_off_by_one
- t_asan_uaf

Each tests checks:
- regular build
- 32-bit
- PIC
- PIE
- profile

These tests require paxctl(8) to disable ASLR in order to work in a
predictable way. This is especially true for all !regular builds with
additional compiler flags.

There are no static variations of these tests as this mode is not supported
in upstream ASan.

Enable these tests on amd64 and i386.

Patch submitted by <Siddharth Muralee>
Additional polishing by myself.

branches: 1.1.2; 1.1.32;
Deprecate tests/toolchain.