GNU patch through 2.7.6 is vulnerable to OS shell command injection that
can be exploited by opening a crafted patch file that contains an ed style
diff payload with shell metacharacters. The ed editor does not need to be
present on the vulnerable system. This is different from CVE-2018-1000156.

https://nvd.nist.gov/vuln/detail/CVE-2019-13638

Signed-off-by: Russell Senior <russell@personaltelco.net>