Re: [bug-libunistring] Improve build parallelization patch submitted to vcpkg

[Bruno Haible]

Hi,

Billy O'Neal wrote:
> A contributor has asked to apply a patch to libunistring to improve build 
> time by parallelizing some of the operations in the makefile: 
> https://github.com/microsoft/vcpkg/pull/27819/
> 
> Would you be willing to look at this patch and take it or indicate that you 
> don't oppose vcpkg applying it?

As far as I understand the patch [1], it parallelizes a loop that compiles many
source files and collects the symbols defined by the resulting .o files, such
that
  - the total elapsed time will shrink significantly (depending on the number
    of CPUs available),
  - the total CPU time remains the same,
  - there is a code duplication: ca. 12 lines of code are duplicated,
  - the resulting Makefile will not work any more with non-GNU make.

Therefore the patch is not appropriate for upstream.

Whether vcpkg applies it or not, is your choice. Whether optimizing the
elapsed time of a build is worth the cost of maintaining a patch that
cannot be upstreamed. Your choice.

Bruno

[1] 
https://raw.githubusercontent.com/microsoft/vcpkg/5cad6642fcc4dcc2909fc4ecf3fc1b5f6b3d01be/ports/libunistring/parallelize-symbol-collection.patch