build: fix cctest compilation

Currently the cctest target compiles sources files even though they are
compiled for the node target. This is my fault as when I worked on the
task of getting the cctest to use the object files from the node target
I missed a few sources that were being included from node.gypi. This
also effects the build time as these sources are compiled twice.

This commit moves the conditions in question into the node target in
node.gyp. With this commit there should be no object files in
out/Release/obj.target/cctest/src/ (the path will vary depending on the
operating system being used).

PR-URL:https://github.com/nodejs/node/pull/16887
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

1 files changed, 5 insertions, 0 deletions

diff --git a/doc/guides/writing-tests.md b/doc/guides/writing-tests.md
index 6868e8681c..19626799f7 100644
--- a/doc/guides/writing-tests.md
+++ b/doc/guides/writing-tests.md
@@ -325,6 +325,11 @@ Next add the test to the `sources` in the `cctest` target in node.gyp:
   ...
 ],
 ```
+Note that the only sources that should be included in the cctest target are
+actual test or helper source files. There might be a need to include specific
+object files that are compiled by the `node` target and this can be done by
+adding them to the `libraries` section in the cctest target.
+
 The test can be executed by running the `cctest` target:
 ```console
 $ make cctest