Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 104 insertions, 0 deletions

diff --git a/src/zstd/build/cmake/README.md b/src/zstd/build/cmake/README.md
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+# Cmake contributions
+
+Contributions to the cmake build configurations are welcome. Please
+use case sensitivity that matches modern (ie. cmake version 2.6 and above)
+conventions of using lower-case for commands, and upper-case for
+variables.
+
+## How to build
+
+As cmake doesn't support command like `cmake clean`, it's recommended to perform a "out of source build".
+To do this, you can create a new directory and build in it:
+```sh
+cd build/cmake
+mkdir builddir
+cd builddir
+cmake ..
+make
+```
+Then you can clean all cmake caches by simply delete the new directory:
+```sh
+rm -rf build/cmake/builddir
+```
+
+And of course, you can directly build in build/cmake:
+```sh
+cd build/cmake
+cmake
+make
+```
+
+To show cmake build options, you can:
+```sh
+cd build/cmake/builddir
+cmake -LH ..
+```
+
+Bool options can be set to `ON/OFF` with `-D[option]=[ON/OFF]`. You can configure cmake options like this:
+```sh
+cd build/cmake/builddir
+cmake -DZSTD_BUILD_TESTS=ON -DZSTD_LEGACY_SUPPORT=ON ..
+make
+```
+
+### referring
+[Looking for a 'cmake clean' command to clear up CMake output](https://stackoverflow.com/questions/9680420/looking-for-a-cmake-clean-command-to-clear-up-cmake-output)
+
+## CMake Style Recommendations
+
+### Indent all code correctly, i.e. the body of
+
+ * if/else/endif
+ * foreach/endforeach
+ * while/endwhile
+ * macro/endmacro
+ * function/endfunction
+
+Use spaces for indenting, 2, 3 or 4 spaces preferably. Use the same amount of
+spaces for indenting as is used in the rest of the file. Do not use tabs.
+
+### Upper/lower casing
+
+Most important: use consistent upper- or lowercasing within one file !
+
+In general, the all-lowercase style is preferred.
+
+So, this is recommended:
+
+```
+add_executable(foo foo.c)
+```
+
+These forms are discouraged
+
+```
+ADD_EXECUTABLE(bar bar.c)
+Add_Executable(hello hello.c)
+aDd_ExEcUtAbLe(blub blub.c)
+```
+
+### End commands
+To make the code easier to read, use empty commands for endforeach(), endif(),
+endfunction(), endmacro() and endwhile(). Also, use empty else() commands.
+
+For example, do this:
+
+```
+if(FOOVAR)
+   some_command(...)
+else()
+   another_command(...)
+endif()
+```
+
+and not this:
+
+```
+if(BARVAR)
+   some_other_command(...)
+endif(BARVAR)
+```
+
+### Other resources for best practices
+
+https://cmake.org/cmake/help/latest/manual/cmake-developer.7.html#modules