Fix #11780 FN uninitvar with clock_settime() / Partial fix for #11617… #19355

Job	Run time
build_cmake (alpine:3.23, false, false)	4m 15s
build_make (ubuntu:25.10)	3m 39s
build_cmake (ubuntu:24.04, true, true)	5m 30s
build_cmake (ubuntu:25.10, true, true)	2m 44s
build_make (ubuntu:24.04)	4m 28s
build_make (alpine:3.23)	6m 4s
	26m 40s

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