Getting pthreads cflags and library flags from Threads::Threads

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I am porting a C library from autotools to cmake. The library depends on pthreads, which with autotools is detected using an AX_PTHREAD macro from an ax_pthread.m4 file. This macro sets PTHREAD_LIBS and PTHREAD_CFLAGS appropriately for the target platform.

In cmake, I am replacing this with a find_package(Threads REQUIRED) and target_link_libraries( ... Threads::Threads).

One thing I can’t figure out how to do however is this: my library has a .pc file for pkg-config which is generated (currently by autotools) from a .pc.in file which relies on PTHREAD_LIBS and PTHREAD_CFLAGS to know what cflags and libs pkg-config should return. I am replacing the generation of this .pc file with cmake’s configure_file (...), but I don’t know how to get the equivalent of PTHREAD_LIBS and PTHREAD_CFLAGS from the Threads::Threads target. How can I do that?

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You should be able to use $<TARGET_PROPERTY:Threads::Threads:INTERFACE_COMPILE_OPTIONS> and the like. You’ll then need file(GENERATE) instead of configure_file().