Compilation with Mingw-w64 (g++ 5.2.0 and 9.2.0) fails (Boost 1.71.0)

When trying to compile the example code from this question: https://stackoverflow.com/questions/49453476/using-boost-thread-pool-executor-submit-method
compilation fails and this error message is given by both g++ 5.2.0 and g++ 9.2.0 (as part of Mingw-w64):

mingw32-make -j20 all
g++ -c -pipe -isystem C:\Libraries\OpenCascade\oce\InstallMingw64\include\oce -isystem C:\Libraries\boost_1_71_0 -std=gnu++1y -Wpedantic -ffunction-sections -fdata-sections -mtune=generic -O2 -DNDEBUG -frtti -fexceptions -mthreads -Wall -Wextra -DUNICODE -DQT_DLL -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_SSE -DQT_HAVE_MMXEXT -DQT_HAVE_SSE2 -DQT_THREAD_SUPPORT -DQT_NEEDS_QMAIN -I [... here come the include directories] -o Main.o ..\src\Main.cpp
In file included from C:\Libraries\boost_1_71_0/boost/thread/detail/thread.hpp:26:0,
from C:\Libraries\boost_1_71_0/boost/thread/thread_only.hpp:22,
from C:\Libraries\boost_1_71_0/boost/thread/thread.hpp:12,
from C:\Libraries\boost_1_71_0/boost/thread.hpp:13,
from ..\src\Main.cpp:7:
C:\Libraries\boost_1_71_0/boost/thread/detail/invoke.hpp: In function 'decltype (*(forward)(*boost::detail::invoke::a0).**boost::detail::invoke::f) boost::detail::invoke(Fp&&, A0&&) [with Fp = void (boost::executors::basic_thread_pool::*)(); A0 = boost::executors::basic_thread_pool*; decltype (*(forward)(*boost::detail::invoke::a0).**boost::detail::invoke::f) = void (boost::executors::basic_thread_pool::)()]':
C:\Libraries\boost_1_71_0/boost/thread/detail/invoke.hpp:102:43: internal compiler error: in gimplify_expr, at gimplify.c:8786
return (*boost::forward(a0)).*f;
^
libbacktrace could not find executable to open
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mingw32-make: *** [Main.o] Error 1
Makefile:187: recipe for target 'Main.o' failed
"mingw32-make -j20 all" terminated with exit code 2. Build might be incomplete.