Link to wiki page if first git clone fails

README.md

@@ -7,10 +7,11 @@ Package build scripts live in the [`pmaports`](https://gitlab.com/postmarketOS/p
 
 ## Requirements
 * 2 GB of RAM recommended for compiling
-* Linux distribution (`x86`, `x86_64`, or `aarch64`)
+* Linux distribution on the host system (`x86`, `x86_64`, or `aarch64`)
   * [Windows subsystem for Linux (WSL)](https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux) does **not** work! Please use [VirtualBox](https://www.virtualbox.org/) instead.
   * Kernels based on the grsec patchset [do **not** work](https://github.com/postmarketOS/pmbootstrap/issues/107) *(Alpine: use linux-vanilla instead of linux-hardened, Arch: linux-hardened [is not based on grsec](https://www.reddit.com/r/archlinux/comments/68b2jn/linuxhardened_in_community_repo_a_grsecurity/))*
   * On Alpine Linux only: `apk add coreutils`
+  * [Linux kernel 3.17 or higher](https://postmarketos.org/oldkernel)
 * Python 3.4+
 * OpenSSL
 

pmb/helpers/git.py

@@ -49,7 +49,13 @@ def clone(args, name_repo, shallow=True, chown_to_user=False):
         # Run the command
         pmb.chroot.user(args, ["git", "clone"] + options +
                               [pmb.config.git_repos[name_repo], name_temp],
-                        working_dir="/home/pmos/git/")
+                        working_dir="/home/pmos/git/", check=False,
+                        output="stdout")
+        if not os.path.exists(args.work + "/cache_git/" + name_temp):
+            logging.info("NOTE: cloning from git is known to fail when the"
+                         " host linux kernel is older than 3.17:"
+                         " <https://postmarketos.org/oldkernel>")
+            raise RuntimeError("git clone failed!")
 
     # Chown to user's UID and GID
     if chown_to_user: