CMake < 3.11 doesn't support add_library() without any source file
(i.e add_library(foo SHARED)). But flann CMake use a trick that use
an empty string "" as source list (i.e add_library(foo SHARED "")).
This look like a bug in CMake < 3.11.
With CMake >= 3.11, the new behaviour of add_library() break the
existing flann CMake code.
>From CMake Changelog [1]:
"add_library() and add_executable() commands can now be called without
any sources and will not complain as long as sources are added later
via the target_sources() command."
Note: flann CMake code doesn't use target_sources() since no source file
are provided intentionally since the flann shared library is created by
linking with the flann_cpp_s static library with this line:
target_link_libraries(flann_cpp -Wl,-whole-archive flann_cpp_s -Wl,-no-whole-archive)
If you try to use "add_library(flann_cpp SHARED ${CPP_SOURCES})" (as it should
be normally done), the link fail due to already defined symbol.
They are building the shared version using the static library "to speedup the
build time" [3]
This issue is already reported upstream [2] with a proposed solution.
Fixes:
http://autobuild.buildroot.net/results/b2f/b2febfaf8c44ce477b3e4a5b9b976fd25e8d7454
[1] https://cmake.org/cmake/help/v3.11/release/3.11.html
[2] https://github.com/mariusmuja/flann/issues/369
[3]
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configs | ||
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linux | ||
package | ||
support | ||
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toolchain | ||
utils | ||
.defconfig | ||
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CHANGES | ||
Config.in | ||
Config.in.legacy | ||
COPYING | ||
DEVELOPERS | ||
Makefile | ||
Makefile.legacy | ||
README |
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