The various git gitweb tests require that the perl Time::HiRes and
HTML::Entities modules be present in order for the tests to work.
If they aren't located, then the tests should be skipped.

The check for Time::HiRes is already present in gitweb-lib.sh post 2.12.0,
but the other check has been sent upstream.

--- git-2.12.0/t/gitweb-lib.sh.orig	2017-03-20 12:16:52.497642511 +0000
+++ git-2.12.0/t/gitweb-lib.sh	2017-03-20 12:15:20.396763506 +0000
@@ -114,4 +114,14 @@
 	test_done
 }
 
+perl -mTime::HiRes -e 0 >/dev/null 2>&1 || {
+	skip_all='skipping gitweb tests, Time::HiRes module not available'
+	test_done
+}
+
+perl -mHTML::Entities -e 0 >/dev/null 2>&1 || {
+        skip_all='skipping gitweb tests, HTML::Entities module not available'
+        test_done
+}
+
 gitweb_init