Fix C++1 generation of function pointers. #891

Job	Run time
ubu-24 \| g++-14 \| c++2b \| libstdc++ \| ubuntu-24.04	16m 47s
mac-13 \| clang++-15 \| c++2b \| default \| macos-13	8m 4s
mac-13 \| clang++ \| c++2b \| default \| macos-13	5m 13s
ubu-24 \| g++-13 \| c++2b \| libstdc++ \| ubuntu-24.04	5m 47s
ubu-24 \| clang++-19 \| c++20 \| libstdc++ \| ubuntu-24.04	9m 43s
ubu-24 \| clang++-19 \| c++23 \| libc++-18-dev \| ubuntu-24.04	7m 47s
ubu-22 \| clang++-15 \| c++20 \| libc++-15-dev \| ubuntu-22.04	5m 46s
ubu-22 \| clang++-15 \| c++20 \| libstdc++ \| ubuntu-22.04	5m 46s
mac-14 \| clang++ \| c++2b \| default \| macos-14	2m 58s
win-22 \| cl.exe \| c++latest \| default \| windows-2022	40s
win-22 \| cl.exe \| c++20 \| default \| windows-2022	27s
aggregate-results	3s
	1h 9m 1s

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