remove unused header files #40

Job	Run time
macOS / release / homebrew-clang	7m 6s
macOS / debug / homebrew-clang	6m 16s
macOS / release / system-clang	3m 57s
macOS / debug / system-clang	4m 40s
Windows / release / msvc	30m 29s
Windows / release / clang-cl	17m 26s
Windows / release / llvm	16m 43s
Windows / debug / msvc	29m 32s
Windows / debug / clang-cl	15m 33s
Windows / debug / llvm	17m 21s
	2h 29m 3s

Provide feedback