Round out environment setup; restore mode stuff

site_scons/site_init.py

@@ -15,19 +15,6 @@ LIB_DIR = Dir('#lib')
 SRC_DIR = Dir('#src')
 TEST_DIR = Dir('#test')
 
-#
-# SCons Command Line Options
-#
-
-AddOption('--show-build-cmds',
-          dest='build_cmds',
-          action='store_true',
-          help='Show build commands instead of friendly build messages')
-AddOption('--mode',
-          dest='mode',
-          metavar='MODE',
-          help='The build mode')
-
 #
 # Environment Configuration
 #
@@ -38,14 +25,48 @@ def has_clang(env):
     return any([cc_tail.startswith('clang'), cxx_tail.startswith('clang')])
 
 default_env = SCons.Defaults.DefaultEnvironment()
-default_env['CC'] = binaries.first(['clang', 'gcc'])
-default_env['CXX'] = binaries.first(['clang++', 'g++'])
+default_env.Replace(CC=binaries.first(['clang', 'gcc']),
+                    CXX=binaries.first(['clang++', 'g++']))
 
-default_env.Append(CCFLAGS=['-Wall', '-Wextra', '-pedantic'])
+default_env.Append(CCFLAGS=['-Wall', '-Wextra', '-pedantic'],
+                   CFLAGS=['-std=c99'],
+                   CXXFLAGS=['-std=c++11'])
 if has_clang(default_env):
     # Only clang supports color.
     default_env.Append(CCFLAGS=['-fcolor-diagnostics'])
-default_env.Append(CFLAGS=['-std=c99'])
-default_env.Append(CXXFLAGS=['-std=c++11'])
 
 
+debug_env = default_env.Clone(MODE='debug',
+                              CCFLAGS=['-O0', '-g'],
+                              CPPDEFINES=['DEBUG'])
+release_env = default_env.Clone(MODE='release',
+                                CCFLAGS=['-O2'],
+                                CPPDEFINES=['RELEASE'])
+
+MODES = {
+    'debug': debug_env,
+    'release': release_env
+}
+
+#
+# Command Line Options
+#
+
+def process_modes_option(option, opt, value, parser):
+    modes = value.split(',')
+    for m in modes:
+        setattr(parser.values, 'modes', set(modes))
+
+AddOption('--show-build-cmds',
+          dest='build_cmds',
+          action='store_true',
+          help='Show build commands instead of friendly build messages')
+AddOption('--modes',
+          type='string',
+          action='callback',
+          dest='modes',
+          metavar='MODES',
+          default=set(['debug']),
+          callback=process_modes_option,
+          help=('A comma separated list of modes. Choose from: {}. Default is '
+                'debug.').format(', '.join(MODES.keys())))