Possible develop config issue on arm32

From: Tom Kent (lists_at_[hidden])
Date: 2022-06-25 12:59:49

I have a regression runner running on raspberry pi 32-bit architecture (in
addition to a one on 64-bit raspberry pi and tons of X86).

gcc-8 builds fine in both master and develop

clang-9 builds fine on master

clang-9 running the same command line, just on develop, has errors like
this [1], finding basic includes:

```
  "clang++-9" -c -x c++ -Wno-c99-extensions -std=c++2a -O0 -fno-inline
-Wall -g --target=arm-pc-linux -Wno-deprecated-declarations
-DBOOST_ALL_NO_LIB=1 -DBOOST_BEAST_ALLOW_DEPRECATED
-DBOOST_BEAST_SEPARATE_COMPILATION -DBOOST_TEST_NO_AUTO_LINK=1 -I".." -o
"/mnt/fs1/teeks99-05/run/results/boost/bin.v2/libs/accumulators/test/count.test/clang-linux-9~c++2a/debug/link-static/count.o"
"../libs/accumulators/test/count.cpp"

clang: warning: unknown platform, assuming -mfloat-abi=soft
clang: warning: unknown platform, assuming -mfloat-abi=soft
In file included from ../libs/accumulators/test/count.cpp:6:
In file included from ../boost/test/unit_test.hpp:18:
In file included from ../boost/test/test_tools.hpp:17:
In file included from ../boost/config.hpp:44:
../boost/config/detail/select_stdlib_config.hpp:26:14: fatal error:
'cstddef' file not found
#    include <cstddef>
             ^~~~~~~~~
1 error generated.

```

The relevant line of the user-config.jam is:
using clang : 9~c++2a : clang++-9 : <cxxflags>"-Wno-c99-extensions -std=c++2a" ;

The two command lines being run are:

run.py --runner=teeks99-05-mc9-2a-32onarmv7l --toolsets=clang-9~c++2a          \
  "--bjam-options=-j4 address-model=32 --remove-test-targets"                  \
  --comment=info.html --tag=master

run.py --runner=teeks99-05-dc9-2a-32onarmv7l --toolsets=clang-9~c++2a          \
  "--bjam-options=-j4 address-model=32 --remove-test-targets"                  \
  --comment=info.html --tag=develop

Any ideas why master and develop would be different in this regard?
Something with B2 changes?

Thanks,

Tom

[1] https://www.boost.org/development/tests/develop/developer/output/teeks99-05-dc9-2a-32onarmv7l-boost-bin-v2-libs-accumulators-test-count-test-clang-linux-9~c++2a-debug-link-static.html