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build: Enhance Ccache performance across worktrees and build trees

Placeholder Hennadii Stepanov requested to merge github/fork/hebasto/240910-ccache into master

To maximize performance, it is essential to follow the recommendations in the Productivity Notes: set the base_dir Ccache configuration option or use the CCACHE_BASEDIR environment variable:

$ export CCACHE_BASEDIR=$HOME

Here are examples of usage on Ubuntu 24.04:

  1. Across different worktrees:
$ export CCACHE_DIR=$(mktemp -d)
$ git worktree add ../wt_1 4d3f360e2af94f4ed46dc0943196d548da82003e
$ pushd ../wt_1
$ cmake -B build -DWITH_CCACHE=ON
$ cmake --build build -t bitcoind -j $(nproc)
$ popd
$ git worktree add ../wt_2 4d3f360e2af94f4ed46dc0943196d548da82003e
$ pushd ../wt_2
$ cmake -B build -DWITH_CCACHE=ON
$ ccache --zero-stats
$ cmake --build build -t bitcoind -j $(nproc)
$ popd
$ ccache --show-stats
Cacheable calls:    302 / 302 (100.0%)
  Hits:             302 / 302 (100.0%)
    Direct:         302 / 302 (100.0%)
    Preprocessed:     0 / 302 ( 0.00%)
  Misses:             0 / 302 ( 0.00%)
Local storage:
  Cache size (GiB): 0.2 / 5.0 ( 3.31%)
  Hits:             302 / 302 (100.0%)
  Misses:             0 / 302 ( 0.00%)
  1. Across different build trees:
$ export CCACHE_DIR=$(mktemp -d)
$ cmake -B build_1 -DWITH_CCACHE=ON
$ cmake --build build_1 -t bitcoind -j $(nproc)
$ cmake -B build_2 -DWITH_CCACHE=ON
$ ccache --zero-stats
$ cmake --build build_2 -t bitcoind -j $(nproc)
$ ccache --show-stats
Cacheable calls:    302 / 302 (100.0%)
  Hits:             302 / 302 (100.0%)
    Direct:         302 / 302 (100.0%)
    Preprocessed:     0 / 302 ( 0.00%)
  Misses:             0 / 302 ( 0.00%)
Local storage:
  Cache size (GiB): 0.2 / 5.0 ( 3.31%)
  Hits:             302 / 302 (100.0%)
  Misses:             0 / 302 ( 0.00%)

This PR addresses this comment:

However, ccache does not hit across two different build dirs, compiling the same commit.

Fixes https://github.com/bitcoin/bitcoin/issues/31771.

Form https://github.com/bitcoin/bitcoin/actions/runs/13215680798/job/36894673006:

...
Treat compiler warnings as errors ..... ON
Use ccache for compiling .............. Built-in ccache support for the 'Visual Studio 17 2022' generator is not available.


-- Configuring done (300.1s)
-- Generating done (1.2s)
-- Build files have been written to: D:/a/bitcoin/bitcoin/build

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