[PATCH 1/7] meson: avoid recompiling HTTP sources several times

We only link curl into a subset of our subcommands. Consequently, as both "http.c" and "http-walker.c" depend on curl, we don't compile these into "libgit.a" but instead only link those into the commands that depend on curl.

In Meson, we wire these dependencies into the target executables by using the `sources:` keyword. But this has the consequence that we're recompiling those multiple several times, once for every different command they are linked into. In fact, each of these sources is compiled seven times, which of course has an impact on compilation speed.

Fix this issue by instead linking these into a static library so that they only need to be compiled once. This gives us an almost 10% speedup in a clean build:

  Benchmark 1: meson compile (version = HEAD~)
    Time (mean ± σ):      6.781 s ±  0.052 s    [User: 100.775 s, System: 22.954 s]
    Range (min … max):    6.709 s …  6.867 s    10 runs

  Benchmark 2: meson compile (version = HEAD)
    Time (mean ± σ):      6.274 s ±  0.021 s    [User: 91.882 s, System: 22.092 s]
    Range (min … max):    6.242 s …  6.306 s    10 runs

  Summary
    meson compile (version = HEAD) ran
      1.08 ± 0.01 times faster than meson compile (version = HEAD~)

Signed-off-by: Patrick Steinhardt <ps@pks.im>
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 meson.build | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)