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. However, that may produce no result or

# a result that is not version-specific (i.e., just ".../SDKs/MacOSX.sdk").

# Using a version-specific sysroot seems desirable, so if there are 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.

# 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`