bug#32927: 27.0.50; libxml not found when building on macOS Mojave

[Philipp Stephani]

YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> schrieb am Do., 4. Okt. 2018 um 07:24 Uhr:

On Thu, 04 Oct 2018 08:10:35 +0900,
Glenn Morris wrote:
>
>
> Is this the perennial "xcode-select --install" issue again?
>
> Bug#18779, 22552, 24068, 27526#74, 29931, ...
> https://lists.gnu.org/r/emacs-devel/2015-11/msg01926.html

I've received a similar report for the Mac port, and the situation was
a bit different.  Unlike the previous versions, the Command Line Tools
package for Xcode 10 no longer installs the header files into
/usr/include on macOS 10.14 (*).

*: https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes

The culprit for the above case was the bogus libxml-2.0.pc file that
refers to nonexistent /usr/include.  Philipp, could you try

  $ pkg-config --cflags --libs "libxml-2.0 > 2.6.17

to see if it refers to /usr/include ?  If so, locate the erroneous
config file by the following command:

  $ pkg-config --variable pcfiledir "libxml-2.0 > 2.6.17"

Yes, looks like this is the problem:

$ pkg-config --cflags --libs "libxml-2.0 > 2.6.17"

-I/usr/include/libxml2 -lxml2

$ pkg-config --variable pcfiledir "libxml-2.0 > 2.6.17"

/usr/local/Homebrew/Library/Homebrew/os/mac/pkgconfig/10.12

And xcode-select --install doesn't help (because /usr/include doesn't exist).