RFR: 8319197: Exclude hb-subset and hb-style from compilation

[Daniel Jeliński]

On Mon, 6 Nov 2023 13:09:08 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

>> @djelinski Just curious; what would the effect be to both include this change and setting the NO_* defines?
>> 
>> If all the references to these defines are made in the excluded files then the only reason for doing that would be some kind of information to subsequent readers of the code, but they might also be checked elsewhere, and thus give an additional speedup.
>
> HB_NO_SUBSET_CFF is indeed referenced in 2 header files, which are in turn included somewhere else.
> I added the defines on top of the excludes, but this resulted in no measurable build time difference.

Out of curiosity, I tried building with [HB_LEAN](https://github.com/openjdk/jdk/blob/2d4bbf478745e62584420bfdef5a4948edac54ad/src/java.desktop/share/native/libharfbuzz/hb-config.hh#L57), which is a shortcut for "no optional features"; I got a couple of new warnings, and one error (`hb_font_funcs_set_glyph_v_kerning_func` is deprecated since 2.0 and not compiled with HB_LEAN; fortunately its use in hb-jdk-font.cc can be simply commented out). After resolving these problems, fontmanager compiled successfully - but again, no measurable time difference.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16440#discussion_r1383335397