bug#29931: 27.0.50; Slightly suboptimal build behavior on macOS

[Alan Third]

On Mon, Jan 01, 2018 at 03:12:57PM +0000, Philipp Stephani wrote:
> Philipp Stephani <p.stephani2@gmail.com> schrieb am Mo., 1. Jan. 2018 um
> 16:05 Uhr:
> 
> > Alan Third <alan@idiocy.org> schrieb am Mo., 1. Jan. 2018 um 15:59 Uhr:
> >
> >> On Mon, Jan 01, 2018 at 01:15:09PM +0100, Philipp wrote:
> >> >
> >> > There are a few small bugs when building on macOS and not passing the
> >> > right configure options.
> >> >
> >> > 1. When running configure without options, the build fails with an error
> >> >
> >> > xml.c:26:10: fatal error: 'libxml/tree.h' file not found
> >> > #include <libxml/tree.h>
> >> >          ^~~~~~~~~~~~~~~
> >> >
> >> > Apparently configure detects libxml2 to be present, but doesn't set the
> >> > correct include path.
> >>
> >> This works fine here. Is it possible this was introduced by macOS
> >> 10.13?
> >>
> >> Do you see the file in /usr/include/libxml2/libxml/?
> >>
> >
> > No, /usr/include doesn't exist at all on my system. The include directory
> > is
> > /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include.
> >
> 
> `xcode-select --install` does add a /usr/include directory. If
> `xcode-select --install` is necessary for building Emacs, should configure
> error out if it hasn't been run?
> However, all other parts of the build process seem to work fine without
> `xcode-select --install`.

Can you please run

    xcrun --show-sdk-path

And see if it returns something useful? On my machine it returns
nothing at all, but I don’t have the full xcode installed.
-- 
Alan Third