Speedups: remove dependency on c++ (#2796)

* Speedups: remove dependency on c++

* Speedups: intset: handle malloc failing

* Speedups: intset: fix corner case for int64 on 32bit systems

original idea was to only use bucket->val if int<pointer,
but we always have a union now anyway

* Speedups: add size comment to player_set bucket configuration

* test: more tests for LocationStore.find_item

* test: require _speedups in CI

This kind of tests that the build succeeds.

* test: even more tests for LocationStore.find_item

* Speedups: intset uniform comment style

* Speedups: intset: avoid memory leak when realloc fails

* Speedups: intset: make `gcc -pedantic -std=c99 -fanalyzer` without warnings

Unnamed unions are not in C99, this got fixed.
The overhead of setting count=0 is minimal or optimized-out and silences -fanalizer (see comment).

* Speedups: don't leak memory in case of exception

* Speedups: intset: validate alloc and free

This won't happen in our cython, but it's still a good addition.

* CI: add test framework for C/C++ code

* CI: ctest: fix cwd

* Speedups: intset: ignore msvc warning

* Tests: intset: revert attempt at no-asan

We solve this with env vars in ctest now, and this fails for msvc.

* Test: cpp: docs: fix typo

* Test: cpp: docs: fix another typo

* Test: intset: proper bucket count for Negative test

INTxx_MIN % 1 would not produce a negative number, so the test was flawed.

test/cpp/CMakeLists.txt

@@ -0,0 +1,49 @@
+cmake_minimum_required(VERSION 3.5)
+project(ap-cpp-tests)
+
+enable_testing()
+
+find_package(GTest REQUIRED)
+
+if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    add_definitions("/source-charset:utf-8")
+    set(CMAKE_CXX_FLAGS_DEBUG "/MTd")
+    set(CMAKE_CXX_FLAGS_RELEASE "/MT")
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    # enable static analysis for gcc
+    add_compile_options(-fanalyzer -Werror)
+    # disable stuff that gets triggered by googletest
+    add_compile_options(-Wno-analyzer-malloc-leak)
+    # enable asan for gcc
+    add_compile_options(-fsanitize=address)
+    add_link_options(-fsanitize=address)
+endif ()
+
+add_executable(test_default)
+
+target_include_directories(test_default
+        PRIVATE
+        ${GTEST_INCLUDE_DIRS}
+)
+
+target_link_libraries(test_default
+        ${GTEST_BOTH_LIBRARIES}
+)
+
+add_test(
+        NAME test_default
+        COMMAND  test_default
+)
+
+set_property(
+        TEST test_default
+        PROPERTY ENVIRONMENT "ASAN_OPTIONS=allocator_may_return_null=1"
+)
+
+file(GLOB ITEMS *)
+foreach(item ${ITEMS})
+    if(IS_DIRECTORY ${item} AND EXISTS ${item}/CMakeLists.txt)
+        message(${item})
+        add_subdirectory(${item})
+    endif()
+endforeach()