Fix googlebenchmark support in O2

[dberzano]

• Make googlebenchmark a build requirement: it produces a static library
  therefore it is not needed at runtime
• Add a Modulefile for googlebenchmark for completeness

[dberzano]

@aphecetche can you check?

[alibuild]

Error while checking build/O2/alidist for 93013a4:

sw/BUILD/O2-latest/log
[36016]: global-config                                   = require-me                                                                             <string>         [provided]
[36016]: id                                              = consumer                                                                               <string>         [provided]
[36016]: initialization-timeout                          = 120                                                                                    <int>            [default] 
[36016]: io-threads                                      = 1                                                                                      <int>            [default] 
[36016]: local-option                                    = hello-aliceo2                                                                          <string>         [provided]
[36016]: log-to-file                                     =                                                                                        <string>         [default] 
[36016]: network-interface                               = default                                                                                <string>         [default] 
[36016]: port-range-max                                  = 32000                                                                                  <int>            [default] 
[36016]: port-range-min                                  = 22000                                                                                  <int>            [default] 
[36016]: rate                                            = 0                                                                                      <float>          [default] 
[36016]: session                                         = default                                                                                <string>         [default] 
[36016]: severity                                        = debug                                                                                  <string>         [default] 
[36016]: shm-monitor                                     = 0                                                                                      <bool>           [default] 
[36016]: shm-segment-size                                = 2000000000                                                                             <std::size_t>    [default] 
[36016]: transport                                       = zeromq                                                                                 <string>         [default] 
[36016]: verbosity                                       = medium                                                                                 <string>         [default] 
[36016]: 
[36016]: [14:48:01][STATE] Entering INITIALIZING DEVICE state
[36013]: [14:48:01][INFO] foo[0]: in: -nan (-nan MB) out: -nan (-nan MB)
[36013]: [14:48:01][INFO] from_producer_to_consumer[0]: in: -nan (-nan MB) out: -nan (-nan MB)
[INFO] Quitting
[INFO] QUIT_REQUESTED

[36013]: [14:48:01][INFO] Received device shutdown request (signal 15).
[36013]: [14:48:01][INFO] Waiting for graceful device shutdown. Hit Ctrl-C again to abort immediately.
[36016]: [14:48:01][INFO] Received device shutdown request (signal 15).
[36016]: [14:48:01][INFO] Waiting for graceful device shutdown. Hit Ctrl-C again to abort immediately.
[36016]: [14:48:01][STATE] Entering DEVICE READY state
[36016]: [14:48:01][STATE] Entering INITIALIZING TASK state
[36016]: [14:48:01][STATE] Entering READY state
[36016]: [14:48:01][STATE] Entering RUNNING state
[36016]: [14:48:01][INFO] DEVICE: Running...
[36016]: [14:48:01][STATE] Entering READY state
[36013]: [14:48:02][STATE] Entering READY state
[36013]: [14:48:02][STATE] Entering RESETTING TASK state
[36013]: [14:48:02][STATE] Entering DEVICE READY state
[36013]: [14:48:02][STATE] Entering RESETTING DEVICE state
[36013]: [14:48:02][STATE] Entering IDLE state
[36013]: [14:48:02][STATE] Entering EXITING state
[36013]: [14:48:02][STATE] Exiting FairMQ state machine
[36013]: [14:48:02][INFO] Process 36013 is exiting.


99% tests passed, 1 tests failed out of 176

Total Test time (real) =  71.61 sec

The following tests FAILED:
	156 - test_Framework_test_WorkflowOptions (Timeout)

Full log here.

[aphecetche]

@dberzano now (re)compiling... will report asap

[dberzano]

So in principle it should work for you if we maintain it as a build requirement. googlebenchmark only generates a static library, meaning you won't need the .a any longer when running code linked against it (symbols are copied in your executable/library).

Since this works for us (tests are green) I am merging it now (currently, O2 nightlies are broken without it), but feel free to open a new PR in case you see problems!