#!/bin/sh
#
# Select where system include files should be sought. If the user specified a
# sysroot, validate it.
#
# A separate script so it can be shared between autoconf and meson.

PG_SYSROOT=$1

if test x"$PG_SYSROOT" = x"" ; then
  # This is far more complicated than it ought to be.  We first ask
  # "xcrun --show-sdk-path", which seems to match the default -isysroot
  # setting of Apple's compilers.
  PG_SYSROOT=`xcrun --show-sdk-path 2>/dev/null`
  # That may fail, or produce a result that is not version-specific (i.e.,
  # just ".../SDKs/MacOSX.sdk").  Using a version-specific sysroot seems
  # desirable, so if the path is a non-version-specific symlink, expand it.
  if test -L "$PG_SYSROOT"; then
    if expr x"$PG_SYSROOT" : '.*[0-9]\.[0-9][^/]*$' >/dev/null ; then : okay
    else
      PG_SYSROOT=`expr "$PG_SYSROOT" : '\(.*\)/'`/`readlink "$PG_SYSROOT"`
    fi
  fi
  # If there are still not digits in the directory name, try
  # "xcrun --sdk macosx --show-sdk-path"; and if that still doesn't work,
  # fall back to asking xcodebuild, which is often a good deal slower.
  if expr x"$PG_SYSROOT" : '.*[0-9]\.[0-9][^/]*$' >/dev/null ; then : okay
  else
    PG_SYSROOT=`xcrun --sdk macosx --show-sdk-path 2>/dev/null`
    if expr x"$PG_SYSROOT" : '.*[0-9]\.[0-9][^/]*$' >/dev/null ; then : okay
    else
      PG_SYSROOT=`xcodebuild -version -sdk macosx Path 2>/dev/null`
    fi
  fi
fi
# Validate the result: if it doesn't point at a directory, ignore it.
if test x"$PG_SYSROOT" != x"" ; then
  if test -d "$PG_SYSROOT" ; then
    echo $PG_SYSROOT
  fi
fi