Respect env build settings, dont force crappy flags, and make sure -rpath is added properly.

--- SConstruct
+++ SConstruct
@@ -41,6 +41,18 @@
 debug = buildmode == "debug"
 Export('debug')
 
+import SCons.Util
+if os.environ.has_key('CC'):
+	env['CC'] = os.environ['CC']
+if os.environ.has_key('CFLAGS'):
+	env['CCFLAGS'] += SCons.Util.CLVar(os.environ['CFLAGS'])
+if os.environ.has_key('CXX'):
+	env['CXX'] = os.environ['CXX']
+if os.environ.has_key('CXXFLAGS'):
+	env['CXXFLAGS'] += SCons.Util.CLVar(os.environ['CXXFLAGS'])
+if os.environ.has_key('LDFLAGS'):
+	env['LINKFLAGS'] += SCons.Util.CLVar(os.environ['LDFLAGS'])
+
 if (env['gcc_visibility']): 
 	env.Append(CCFLAGS=' -fvisibility-inlines-hidden -fvisibility=hidden -DGCC_HASCLASSVISIBILITY ')
 	env.Append(CXXFLAGS=' -fvisibility-inlines-hidden -fvisibility=hidden -DGCC_HASCLASSVISIBILITY ')
@@ -81,16 +81,10 @@
 	if env['gcc_visibility']: 
 		env.Append(CCFLAGS=' -fvisibility-inlines-hidden -fvisibility=hidden ');
 		env.Append(CPPFLAGS=' -fvisibility-inlines-hidden -fvisibility=hidden ');
-	if debug:
-		env.Append(CCFLAGS='-ggdb ')
-		env.Append(CPPFLAGS='-ggdb ')
-	else: 
-		env.Append(CCFLAGS='-O3 ')
-		env.Append(CPPFLAGS='-O3 ')
 		
 	al_lib = 'openal'
-	env.Append(CPPFLAGS=' -Wall -pedantic -Wno-long-long -pipe -pthread ')
-	env.Append(CCFLAGS=' -Wall -pedantic -Wno-long-long -pipe -pthread ')
+	env.Append(CPPFLAGS=' -Wall -pedantic -Wno-long-long -pthread ')
+	env.Append(CCFLAGS=' -Wall -pedantic -Wno-long-long -pthread ')
 
 
 conf_env = env.Copy()
--- SConscript
+++ SConscript
@@ -94,7 +94,7 @@
 
 Import('lib_dir')
 if sys.platform != 'win32':
-	bt_env.Append(LINKFLAGS=' -Wl,-rpath '+ lib_dir + ' -Wl,-rpath-link build/' + env['mode'] + '/mrt')
-	bt_env.Append(LINKFLAGS=' -Wl,-rpath '+ lib_dir + ' -Wl,-rpath-link build/' + env['mode'] + '/sdlx')
+	bt_env.Append(LINKFLAGS=' -Wl,-rpath,'+ lib_dir + ' -Wl,-rpath-link,build/' + env['mode'] + '/mrt')
+	bt_env.Append(LINKFLAGS=' -Wl,-rpath,'+ lib_dir + ' -Wl,-rpath-link,build/' + env['mode'] + '/sdlx')
 
 bt_main = bt_env.Program('bt', bt_main_sources, LIBS=bt_main_libs, RPATH=[lib_dir])