src: add missing 'inline' keywords

[bnoordhuis]

Pull Request check-list

• Does make -j8 test (UNIX) or vcbuild test nosign (Windows) pass with
  this change (including linting)?
• Is the commit message formatted according to [CONTRIBUTING.md][0]?
• If this change fixes a bug (or a performance problem), is a regression
  test (or a benchmark) included?
• Is a documentation update included (if this change modifies
  existing APIs, or introduces new ones)?

Affected core subsystem(s)

build, src

Description of change

• src: add missing 'inline' keywords
• build: turn on --gc-sections on linux and freebsd

CI: https://ci.nodejs.org/job/node-test-pull-request/2160/

[bnoordhuis]

Apropos --gc-sections, the alternative is to drop the -fdata-sections and -ffunction-sections flags. I'm on a laptop and I didn't feel like recompiling and benchmarking everything to see if it makes a difference. :-)

[bnoordhuis]

Okay, --gc-sections clearly doesn't work reliably on FreeBSD and pLinux. I've dropped that commit and I'll file a new PR that removes -fdata-sections and -ffunction-sections. CI: https://ci.nodejs.org/job/node-test-pull-request/2164/

[cjihrig]

LGTM

[jasnell]

@bnoordhuis ... does this need to happen in v4 also?

[bnoordhuis]

It's not critical but yes.

[mscdex]

A bit late to the party here but what about the possibility of enabling the flags on known working platforms?

[bnoordhuis]

I didn't run extensive tests but I don't think it's really worth the trouble. It trims about 16K from the 20 MB binary (16 MB stripped) and it seems to negatively impact gcc's ability to do intra-procedural optimizations (maybe not when LTO is enabled but we don't do that, and we wouldn't need the flags in that case anyway.)