[MacPorts] #60987: meson: not finding pkg-config when building universal when using cross-files

[MacPorts]

#60987: meson: not finding pkg-config when building universal when using cross-
files
--------------------+----------------------------
 Reporter:  kencu   |      Owner:  (none)
     Type:  defect  |     Status:  new
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  meson graphene
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 To improve building universal with {{{meson}}} we recently added machine
 cross-files. These are needed when the build configures itself differently
 (eg adding asm files) with different architectures.

 This works, but there is an issue with {{{pkg-config}}}, it appears, first
 noticed when rebuilding {{{graphene +universal}}}.

 {{{meson}}} does not appear to be searching the PATH for {{{pkg-config}}}
 when cross building, but it wants {{{pkg-config}}} to be specified.
 {{{meson}}} actually has a rather complicated (no surprise there)
 algorithm for
 [https://github.com/mesonbuild/meson/blob/847d652c4ef179bbf94c0e322dc3277858fcf08c/mesonbuild/dependencies/base.py#L557
 searching for pkg-confg]  that will take some sorting out.

 One thing that worked is to add the {{{PKG_CONFIG}}} spec to the configure
 environment like this:
 {{{
 configure.env-append PKG_CONFIG=${prefix}/bin/pkg-config
 }}}

 We could do that in the {{{meson}}} PortGroup, I suppose, or each port
 that uses meson and pkg-config could do it individually.

-- 
Ticket URL: <https://trac.macports.org/ticket/60987>
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