CMake WITH_EXTERNAL_LIBMULTIPROCESS and BUILD_FUZZ_BINARY options stopped working together recently due to #35118 commit 037ad77071419367fd679da71d5c39853d1e622e because an non-namespaced Libmultiprocess::multiprocess target name was referenced.
Fix by specifying the full target name which is better for readability anyway.
**What failed:** Build error: 'mp/proxy-io.h' file not found when
building the ipc fuzz target.
**Root cause:** Upstream commit 037ad770714 (fuzz: add IPC round-trip
target) added target_link_libraries(fuzz bitcoin_ipc_fuzz multiprocess)
using the bare 'multiprocess' target, which only exists in subtree
builds. With WITH_EXTERNAL_LIBMULTIPROCESS=ON, no 'multiprocess' cmake
target is defined, so the INTERFACE_INCLUDE_DIRECTORIES from the
installed libmultiprocess headers were never propagated to the fuzz
target, causing the missing-header error.
**Fix:** Changed to 'Libmultiprocess::multiprocess', which is the
canonical namespaced target available in both subtree and external builds.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35715.
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ACK db35b9238fc903c1dcbc0d428b247250d46c3b41
ACK db35b9238fc903c1dcbc0d428b247250d46c3b41, I have reviewed the code and it looks OK.