Random parallel-build failure: No rule to make target liblua51.a

[kelvSYC]

Building the vendored Lua (lua-5.1.5/toluapp-simple) sometimes fails under make -j, but not always — same source, nothing changed in between, and it can pass or fail from one run to the next:

make[5]: *** No rule to make target `liblua51.a', needed by `libtoluapp51.dylib'.  Stop.

Looks like it's this bit in toluapp-simple/CMakeLists.txt:

target_link_libraries(toluapp51 PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})
target_link_libraries(toluapp51_shared PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})
target_link_libraries(toluapp PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})

These link liblua51.a by its raw path instead of the lua51_static target that actually builds it. There's an add_dependencies(...) a few lines down that orders the targets correctly, but since the link step points at a plain file path rather than a CMake target, Make doesn't always know to wait for that specific file before linking against it — so under -j it sometimes wins the race and sometimes doesn't.

Swapping the raw path for the target name fixes it for me:

-    target_link_libraries(toluapp51 PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})
-    target_link_libraries(toluapp51_shared PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})
-    target_link_libraries(toluapp PUBLIC "${PROJECT_BINARY_DIR}/liblua51.a" ${CMAKE_DL_LIBS})
+    target_link_libraries(toluapp51 PUBLIC lua51_static ${CMAKE_DL_LIBS})
+    target_link_libraries(toluapp51_shared PUBLIC lua51_static ${CMAKE_DL_LIBS})
+    target_link_libraries(toluapp PUBLIC lua51_static ${CMAKE_DL_LIBS})

Hit this on macOS arm64 (CMake 3.31+, make -j3), but I don't think it's macOS-specific — seems like it'd depend on job scheduling on any platform using the Makefiles generator.

(Found while working on a from-source CI build; drafted with AI assistance.)