Fix detection of library flavors on FreeBSD
Fix library flavor detection for the validate script as well
Actually test T4175
Improve tests slightly
Error message wibbles, following TcErrors refactoring
Test Trac #7786
Peak-memory usage for T3064 varies depending on whether .hi file exists on not

Really, the existence or otherwise of the .hi file shouldn't affect validate
output, but it seems to.  Maybe 'make clean' doesn't clean enough?

In ay case peak memory usage is a fragile number because it depends on when
GC happens.

So I increased the range to 20% for now.
Error message wibbles
Test Trac #7857
Add a test for "--make -dynamic-too"
dynamic002 is broken (#7864)
Fix the dynamicToo002 test
Update Cabal perf expected values following Cabal update
More dynamic-too tests
dynamicToo002 now passes
Wibbles to error messages, following the fix for Trac #7851

In effect, the error context for naked variables now takes up
a "slot" in the context stack; but it is often empty.  So the
context stack becomes one shorter in those cases.  I don't think
this matters; indeed, it's aguably an improvement.  Anyway that's
why so many tests are affected.
Test Trac #7778
Test Trac #7851
Test Trac #7856
Test Trac #7869