Switch implicit make flags to use GNUMAKEFLAGS var

There are a few notable elements addressed by this change:
1. The --load/-l argument is GNU-only and doesn't work on BSD make
2. The GNUMAKEFLAGS environment variable was previously ignored when
   looking for existing make arguments
3. By passing the flags via command line arguments to CMake's build
   invocation, the makeflags were sometimes omitted due to
   incompatibility.

colcon_cmake/task/cmake/build.py

@@ -84,6 +84,8 @@ async def build(  # noqa: D102
         if environment_callback is not None:
             environment_callback(env)
 
+        self._set_gnumakeflags(env)
+
         rc = await self._reconfigure(args, env)
         if rc:
             return rc
@@ -241,10 +243,6 @@ async def _build(self, args, env, *, additional_targets=None):
                 cmd += ['--clean-first']
             if multi_configuration_generator:
                 cmd += ['--config', self._get_configuration(args)]
-            else:
-                job_args = self._get_make_arguments(env)
-                if job_args:
-                    cmd += ['--'] + job_args
             completed = await run(
                 self.context, cmd, cwd=args.build_base, env=env)
             if completed.returncode:
@@ -282,42 +280,42 @@ def _get_msbuild_environment(self, args, env):
             env['CL'] = ' '.join(cl_split)
         return env
 
-    def _get_make_arguments(self, env):
+    def _set_gnumakeflags(self, env):
         """
-        Get the make arguments to limit the number of simultaneously run jobs.
+        Set GNUMAKEFLAGS to limit the number of simultaneously run jobs.
 
         The arguments are chosen based on the `cpu_count`, e.g. -j4 -l4.
 
         :param dict env: a dictionary with environment variables
-        :returns: list of make arguments
-        :rtype: list of strings
         """
-        # check MAKEFLAGS for -j/--jobs/-l/--load-average arguments
-        makeflags = env.get('MAKEFLAGS', '')
         regex = (
             r'(?:^|\s)'
             r'(-?(?:j|l)(?:\s*[0-9]+|\s|$))'
             r'|'
             r'(?:^|\s)'
             r'((?:--)?(?:jobs|load-average)(?:(?:=|\s+)[0-9]+|(?:\s|$)))'
         )
-        matches = re.findall(regex, makeflags) or []
-        matches = [m[0] or m[1] for m in matches]
-        if matches:
-            # do not extend make arguments, let MAKEFLAGS set things
-            return []
+        # check MAKEFLAGS for -j/--jobs/-l/--load-average arguments
+        makeflags = env.get('MAKEFLAGS', '')
+        if any(m[0] or m[1] for m in re.finditer(regex, makeflags)):
+            return
+        # check GNUMAKEFLAGS for -j/--jobs/-l/--load-average arguments
+        gnumakeflags = env.get('GNUMAKEFLAGS', '')
+        if any(m[0] or m[1] for m in re.finditer(regex, gnumakeflags)):
+            return
+
         # Use the number of CPU cores
         jobs = os.cpu_count()
         with suppress(AttributeError):
             # consider restricted set of CPUs if applicable
             jobs = min(jobs, len(os.sched_getaffinity(0)))
         if jobs is None:
             # the number of cores can't be determined
-            return []
-        return [
-            '-j{jobs}'.format_map(locals()),
-            '-l{jobs}'.format_map(locals()),
-        ]
+            return
+
+        env['GNUMAKEFLAGS'] = f'-j{jobs} -l{jobs}'
+        if gnumakeflags:
+            env['GNUMAKEFLAGS'] += ' ' + gnumakeflags
 
     async def _install(self, args, env):
         self.progress('install')
@@ -326,12 +324,9 @@ async def _install(self, args, env):
             raise RuntimeError("Could not find 'cmake' executable")
         cmd = [CMAKE_EXECUTABLE]
         cmake_ver = get_cmake_version()
-        allow_job_args = True
         if cmake_ver and cmake_ver >= Version('3.15.0'):
             # CMake 3.15+ supports invoking `cmake --install`
             cmd += ['--install', args.build_base]
-            # Job args not compatible with --install directive
-            allow_job_args = False
         else:
             # fallback to the install target which implicitly runs a build
             if not cmake_ver:
@@ -344,9 +339,5 @@ async def _install(self, args, env):
             args.build_base, args.cmake_args)
         if multi_configuration_generator:
             cmd += ['--config', self._get_configuration(args)]
-        elif allow_job_args:
-            job_args = self._get_make_arguments(env)
-            if job_args:
-                cmd += ['--'] + job_args
         return await run(
             self.context, cmd, cwd=args.build_base, env=env)

test/spell_check.words

@@ -13,9 +13,11 @@ ctest
 ctests
 dcmake
 etree
+finditer
 findtext
 getaffinity
 github
+gnumakeflags
 https
 iterdir
 kazys