Add git subtree support to git-scm.org (#1253)

* Add git subtree support to git-scm.org

* fix: git subtree tests

* fix: test

projects/git-scm.org/package.yml

@@ -31,6 +31,11 @@ build:
     ./configure $CONF
     make install $BAKE
 
+    cd contrib/subtree
+    make
+    make install
+    mv git-subtree "{{prefix}}"/libexec
+
     cd "{{prefix}}"
     DEBUG=1 fix-shebangs.ts bin/* libexec/*
 
@@ -69,6 +74,8 @@ test: |
   # necessary to check the libexec binaries work
   git commit --message "test"
 
+  git subtree add --prefix teaxyz-subtree https://github.com/teaxyz/white-paper main --squash
+
 provides:
   - bin/git
   - bin/git-cvsserver