Fix #14629 syntaxError when not/compl is used as identifiers (C) #19171

Job	Run time
build_make (ubuntu:25.10)	3m 47s
build_make (alpine:3.23)	5m 29s
build_cmake (ubuntu:25.10, true, true)	3m 1s
build_make (ubuntu:24.04)	3m 13s
build_cmake (ubuntu:24.04, true, true)	2m 52s
build_cmake (alpine:3.23, false, false)	4m 33s
	22m 55s

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