[boost] libs/regex/build/Jamfile.v2 missing "import testing"

Subject: [boost] libs/regex/build/Jamfile.v2 missing "import testing"
From: Peter Dimov (lists_at_[hidden])
Date: 2016-11-09 20:00:40

In a partial installation (not all submodules installed), running b2 in the 
Boost root says:

libs\regex\build\Jamfile.v2:93: in modules.load
ERROR: rule "unit-test" unknown in module 
"Jamfile<D:\tmp2\boost-root\libs\regex\build>".

because libs/regex/build/Jamfile.v2 uses the unit-test rule, defined in 
testing.jam, but does not have "import testing ;". Adding that line fixes 
it.

I've no idea why it works in a full installation - probably because someone 
else imports testing first before it gets to regex.