+OPTS=""
+%if !0%{?rhel:1} || 0%{?rhel} > 7
+ OPTS="$OPTS --no-tags"
+%endif
+REF="reference"
+# RHEL-7 does not support: --reference-if-able
+test -d ../$REF/ && OPTS="$OPTS --reference ../$REF"
+# 2500 = 1 month in 2019
+git clone --depth 10000 --single-branch $OPTS https://github.com/llvm/llvm-project.git .