[MSVC] Compile error in contract\test\public_function\max_args.hpp

[NEIL-smtg]

Hi, I work on MSVC compiler testing, and we regularly build popular open-source project including Boost, with development builds of MSVC in order to find and fix regressions before they ship and cause problems for you.

Recently, as I build Boost from source with MSVC, I encountered some errors as following:

C:\gitP\boostorg\boost\libs\contract\test\public_function\max_args.hpp(200): error C2065: 'BOOST_CONTRACT_TEST_MAX_ARGS_N_': undeclared identifier
C:\gitP\boostorg\boost\libs\contract\test\public_function\max_args.hpp(199): error C2059: syntax error: ')'
warning C1511: creating 'd:\output\Boost\preprocessed_repro_test\max_args0.rsp' for capture_repro

    call "C:\gitP\boostorg\boost\amd64\boost\bin.v2\standalone\msvc\msvc-14.3\msvc-setup.bat"  >nul
 cl /Zm800 -nologo "libs\contract\test\public_function\max_args0.cpp" -c -Fo"C:\gitP\boostorg\boost\amd64\boost\bin.v2\libs\contract\test\public_function-max_args0.test\msvc-14.3\release\x86_64\threading-multi\public_function\max_args0.obj"     -TP /wd4675 /EHs /GR /Zc:throwingNew /O2 /Ob2 /W3 /MD /Zc:forScope /Zc:wchar_t /Zc:inline /Gw /favor:blend -DBOOST_ALL_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1 -DBOOST_CONTRACT_DYN_LINK -DBOOST_CONTRACT_MAX_ARGS=0 -DNDEBUG "-I." "-Ilibs\contract\test\public_function" 

...failed compile-c-c++ C:\gitP\boostorg\boost\amd64\boost\bin.v2\libs\contract\test\public_function-max_args0.test\msvc-14.3\release\x86_64\threading-multi\public_function\max_args0.obj...

Note: This is only part of the errors, refer test.log.txt for more detail.

Build log: build_log.txt
Test log: Test.log.txt

Steps to reproduce:

1. git clone https://github.com/boostorg/boost.git
2. cd boostorg\boost
3. git fetch --recurse-submodules=no --force
4. git -C "C:\gitP\boostorg\boost" submodule sync
5. git submodule foreach git reset --hard
6. git submodule foreach git clean -xdf
7. git submodule update --init --recursive
8. set _CL_=/DBOOST_TIMER_ENABLE_DEPRECATED
9. .\bootstrap 2>&1
10. .\b2 headers variant=release --build-dir=C:\gitP\boostorg\boost\amd64 address-model=64 architecture=x86 2>&1
11. .\b2 variant=release --build-dir=C:\gitP\boostorg\boost\amd64 address-model=64 architecture=x86 2>&1
12. .\b2 -j16 variant=release --build-dir=C:\gitP\boostorg\boost\amd64 libs\contract\test address-model=64 2>&1