RE: [PATCH] KVM: selftests: add -MP to CFLAGS

From: David Woodhouse

Sent: 28 October 2023 20:35

Using -MD without -MP causes build failures when a header file is deleted or moved. With -MP, the compiler will emit phony targets for the header files it lists as dependencies, and the Makefiles won't refuse to attempt to rebuild a C unit which no longer includes the deleted header.

Won't a phony target stop a header being built if there is an actual rule to build it?

I usually add:

%.h: echo "Ignoring stale dependency for $@"

Which only applies if there isn't an explicit rule.

David

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