Allow offline pre-compilation of 'xsimd' dependency (facebookincubato…

…r#8308)

Summary:
`set(xsimd_SOURCE BUNDLED)` will force the 'xsimd' library to be
compiled from source, but this will make it impossible to compile Velox
offline. We should use `set_source(xsimd)` so that it respects the
`VELOX_DEPENDENCY_SOURCE` global cmake variable.

If it is really needed to force the 'xsimd' library to be compiled from
source in a certain environment, use the following method to achieve it.

```
cmake -Dxsimd_SOURCE=BUNDLED ...
```

Pull Request resolved: facebookincubator#8308

Reviewed By: Yuhta

Differential Revision: D53320172

Pulled By: kgpai

fbshipit-source-id: 8f9fb975ef33ab9596facd1283151f060de545b7

.circleci/dist_compile.yml

@@ -372,6 +372,7 @@ jobs:
       VELOX_DEPENDENCY_SOURCE: SYSTEM
       ICU_SOURCE: BUNDLED
       simdjson_SOURCE: BUNDLED
+      xsimd_SOURCE: BUNDLED
       DuckDB_SOURCE: SYSTEM
     steps:
       - pre-steps

CMakeLists.txt

@@ -544,8 +544,8 @@ if(NOT VELOX_DISABLE_GOOGLETEST)
       PARENT_SCOPE)
 endif()
 
-set(xsimd_SOURCE BUNDLED)
-resolve_dependency(xsimd)
+set_source(xsimd)
+resolve_dependency(xsimd 10.0.0)
 
 if(VELOX_BUILD_TESTING)
   set(BUILD_TESTING ON)