* Support older versions of CMake.
VERSION_GREATER_EQUAL is supported by CMake >=3.7:
https://cmake.org/cmake/help/latest/command/if.html#version-greater-equal
target_link_options() is supported by CMake >=3.13:
https://cmake.org/cmake/help/latest/command/target_link_options.html
* Use PROTOBUF_USE_DLLS and LIBPROTOC_EXPORTS for libprotoc.so shared library
Similar change for libprotobuf.so and libprotobuf-lite.so was made
in commit 5a0887fc65.
* Make value of PROTOC_EXPORT dependent on LIBPROTOC_EXPORTS instead of LIBPROTOBUF_EXPORTS
This was probably intention, and LIBPROTOC_EXPORTS is also used above
in _MSC_VER branch.
Soname was set for libprotobuf.so in commit a9cf69a0ed,
but similar changes for libprotobuf-lite.so and libprotoc.so were missed.
Fixes: #8635
Co-authored-by: Arfrever Frehtes Taifersar Arahesis <Arfrever@GMail.Com>
This updates the CMake support to additionally symlink the soversion value
to the generated shared library when so generated. This aligns the
generated soversion with that traditionally used by the Makefile build
workflow and provides cross-compatibility irrespective of build approach
used.
The primary version of the non-symlink library retains the actual
(non-SO) project version for clarity and compatibility with
installations built using prior versions of CMake support. An example of
the net resulting symlink structures is shown below, where the most
important aspect is that the symlink matching the embedded SONAME is
present (libprotobuf.so.30 in the example case).
Makefile:
libprotobuf.so -> libprotobuf.so.30.0.0
libprotobuf.so.30 -> libprotobuf.so.30.0.0
libprotobuf.so.30.0.0
CMake:
libprotobuf.so -> libprotobuf.so.30
libprotobuf.so.30 -> libprotobuf.so.3.19.0.0
libprotobuf.so.3.19.0.0
Fixes: #8635
Adam Cozzette
Arfrever Frehtes Taifersar Arahesis
appledragon
Joel Johnson
David L. Jones
Joshua Haberman
Bo Yang
Jorge López Fueyo
RPG3D
listonjesse
Rafi Kamal
boscosiu
Hao Nguyen
Aaron Bray
Jozef Izso
Ivan Shynkarenka
Feng Xiao
John Millikin
Corentin Le Molgat
Jisi Liu
Dennis Cappendijk
Byron Yi
Konstantin Podsvirov
Tom Hughes