ci/build.sh: autotools: use OSTYPE to determine if on macOS

OSTYPE is a built-in variable in bash and exists on all operating
systems.

diff --git a/ci/build.sh b/ci/build.sh
index bbd2e47acdb57de0fe907bc0f1971542d26a18b3..0f71357afb8b5d34302032624dd3af37f156f6b6 100755 (executable)
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -48,7 +48,7 @@ else
         (cd graphviz-${GV_VERSION}; fakeroot make -f debian/rules binary) | tee >(ci/extract-configure-log.sh >${META_DATA_DIR}/configure.log)
         mv *.deb ${DIR}/os/${ARCH}/
         mv *.ddeb ${DIR}/debug/${ARCH}/
-    elif [ "${ID}" = "Darwin" ]; then
+    elif [[ "${OSTYPE}" =~ "darwin" ]]; then
         ./autogen.sh
         ./configure --prefix=$( pwd )/build --with-quartz=yes
         make