[gtk-osx: 27/48] Don't set sysroot without an SDK.

[John Ralls <jralls src gnome org>]

commit 681a0a5a2434a95316fc46de21ab9b73ba930250
Author: John Ralls <jralls ceridwen us>
Date:   Sat Apr 13 14:20:45 2019 -0700

    Don't set sysroot without an SDK.

 gtk-osx-setup.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/gtk-osx-setup.sh b/gtk-osx-setup.sh
index ccd6a70..56a462f 100755
--- a/gtk-osx-setup.sh
+++ b/gtk-osx-setup.sh
@@ -205,7 +205,9 @@ export PIPENV_DOTENV_LOCATION="$DEVPREFIX/etc/pipenv-env"
 export PIPENV_PIPFILE="$DEVPREFIX/etc/Pipfile"
 export PATH="$PYENV_ROOT/shims:$DEVPREFIX/bin:$PYENV_INSTALL_ROOT/plugins/python-build/bin:$PATH"
 export PYENV_ROOT
-export CFLAGS="-isysroot $SDKROOT -I$SDKROOT/usr/include"
+if -d "$SDKROOT"; then
+    export CFLAGS="-isysroot $SDKROOT -I$SDKROOT/usr/include"
+fi
 export PYTHON_CONFIGURE_OPTS="--enable-shared"
 export WORKON_HOME=$DEVPREFIX/share/venv