make building the dummy backend be a configure-time option. defaults to False for the time being

libs/backends/wscript

@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 from waflib.extras import autowaf as autowaf
+from waflib import Options
 import os
 import sys
 
@@ -7,11 +8,6 @@ import sys
 top = '.'
 out = 'build'
 
-backends = [ 'jack', 'dummy' ]
-
-if sys.platform == 'darwin':
-    backends += ['wavesaudio' ]
-
 def options(opt):
     autowaf.set_options(opt)
 
@@ -23,9 +19,25 @@ def configure(conf):
     autowaf.set_recursive()
     autowaf.configure(conf)
 
+    backends = [ 'jack' ]
+
+    if sys.platform == 'darwin' or sys.platform == 'mingw' or sys.platform == 'msvc':
+        backends += [ 'wavesaudio' ]
+
+    if Options.options.build_dummy: 
+        backends += [ 'dummy' ]
+
     for i in backends:
         sub_config_and_use(conf, i)
 
 def build(bld):
+    backends = [ 'jack' ]
+
+    if sys.platform == 'darwin' or sys.platform == 'mingw' or sys.platform == 'msvc':
+        backends += [ 'wavesaudio' ]
+
+    if Options.options.build_dummy: 
+        backends += [ 'dummy' ]
+
     for i in backends:
         bld.recurse(i)

wscript

@@ -408,6 +408,8 @@ def options(opt):
                     help='Whether to build for TRX')
     opt.add_option('--arch', type='string', action='store', dest='arch',
                     help='Architecture-specific compiler flags')
+    opt.add_option('--with-dummy', action='store_true', default=False, dest='build_dummy',
+                   help='Build the dummy backend (no audio/MIDI I/O, useful for profiling)')
     opt.add_option('--backtrace', action='store_true', default=True, dest='backtrace',
                     help='Compile with -rdynamic -- allow obtaining backtraces from within Ardour')
     opt.add_option('--no-carbon', action='store_true', default=False, dest='nocarbon',
@@ -783,6 +785,7 @@ const char* const ardour_config_info = "\\n\\
     write_config_text('Build target',          conf.env['build_target'])
     write_config_text('CoreAudio',             conf.is_defined('HAVE_COREAUDIO'))
     write_config_text('Debug RT allocations',  conf.is_defined('DEBUG_RT_ALLOC'))
+    write_config_text('Dummy backend',         opts.build_dummy)
     write_config_text('Process thread timing', conf.is_defined('PT_TIMING'))
     write_config_text('Denormal exceptions',   conf.is_defined('DEBUG_DENORMAL_EXCEPTION'))
     write_config_text('FLAC',                  conf.is_defined('HAVE_FLAC'))