There is an issue with gbenchmark and waf on Ubuntu (15.04 and 15.10, ). Waf doesn't link pthread to gbenchmark and linking failed :
````
[1652/1652] Linking build/linux/libraries/AP_Math/benchmarks/benchmark_matrix.linux
/home/khancyr/Workspace/APM/ardupilot/build/linux/gbenchmark/lib/libbenchmark.a(benchmark.cc.o): dans la fonction « benchmark::RunSpecifiedBenchmarks(benchmark::BenchmarkReporter*) »:
benchmark.cc:(.text+0x2e21): référence indéfinie vers « pthread_create »
/usr/bin/ld generated: référence indéfinie vers « pthread_create »
collect2: error: ld returned 1 exit status
Waf: Leaving directory `/home/khancyr/Workspace/APM/ardupilot/build/linux'
Build failed
-> task in 'benchmark_matrix.linux' failed (exit status 1):
{task 139784788162576: cxxprogram benchmark_matrix.cpp.1.o -> benchmark_matrix.linux}
['/usr/lib/ccache/g++', '-Wl,--gc-sections', 'libraries/AP_Math/benchmarks/benchmark_matrix.cpp.1.o', '-o', '/home/khancyr/Workspace/APM/ardupilot/build/linux/libraries/AP_Math/benchmarks/benchmark_matrix.linux', '-Wl,-Bstatic', '-L.', '-lap', '-Wl,-Bdynamic', '-L/home/khancyr/Workspace/APM/ardupilot/build/linux/gbenchmark/lib', '-lm', '-lpthread', '-lrt', '-lbenchmark']
`````
Adding 'pthread' to env.LIB_GBENCHMARK solve the issue
see https://github.com/diydrones/ardupilot/pull/3460 and https://github.com/diydrones/ardupilot/issues/3461
Some platforms (e.g. bebop) might need to create fully statically linked
binaries. This serves to force a program to be statically linked. It has only
been tested on GNU compilers, other compilers may have unexpected behavior.
The cmake checks for gbenchmark need to run some code. Calling
_configure_cmake() only during build can potentially fail build. That would
happen in some cross-compilations for example.
Those environment variables are set by default by Travis. That fails cross
compilation with waf. There is a GitHub issue open related to that behavior at
https://github.com/travis-ci/travis-ci/issues/4682 . This change can be
reverted if eventually that is fixed.
The TODOs removed with this patch were already fixed. Below is the explanation
for each.
- TODO: add support for unit tests.
- Supported already added.
- TODO: Check if we should simply use the signed 'waf' "binary" (after
verifying it) instead of generating it ourselves from the sources.
- We're using a submodule for waf.
- TODO: evaluate if we need shortcut commands for the common targets
(vehicles). currently using waf --targets=NAME the target name must contain
the board extension so make it less convenient, maybe hook to support
automatic filling this extension?
- There's no need of adding the extension anymore.
- TODO: Once HAL patches get in, need to filter out the HAL based on the
bld.env.BOARD.
- The board-specific HAL library folders is indicated in
bld.env.AP_LIBRARIES.
If there's no variant configuration, then cfg.variant will be '', which will
make bldnode be cfg.bldnode. Thus, this patch prepare gbenchmark build for
variant builds and doesn't break the current build.
We can pass a list of possible binaries to find_program. This gives us a
better output while configuring:
Checking for program 'ninja, ninja-build' : /usr/bin/ninja-build
instead of:
Checking for program 'ninja' : not found
Checking for program 'ninja-build' : /usr/bin/ninja-build
