wscript: refactor opus wscript files, now it builds only if system package wasn't found

scripts/waifulib/opus.py

@@ -1,42 +0,0 @@
-# encoding: utf-8
-
-import os
-
-def options(opt):
-	pass
-
-def configure(conf):
-	path = conf.path.find_dir('3rdparty/opus')
-	conf.env.LIB_OPUS = ['opus']
-	conf.env.INCLUDES_OPUS = [path.find_dir('include/').abspath()]
-
-def build(bld):
-	path = bld.path.find_dir('3rdparty/opus')
-
-	sources = path.ant_glob([
-			'src/*.c',
-			'celt/*.c',
-			'silk/*.c',
-			'silk/float/*.c'])
-
-	includes = [
-		path.find_dir('include/'),
-		path.find_dir('celt/'),
-		path.find_dir('silk/'),
-		path.find_dir('silk/float/')
-	]
-
-	defines = [
-		'USE_ALLOCA',
-		'OPUS_BUILD',
-		'PACKAGE_VERSION="1.3.1"'
-	]
-
-	bld.stlib(
-		source = sources,
-		target = 'opus',
-		features = 'c',
-		includes = includes,
-		defines = defines,
-		subsystem = bld.env.MSVC_SUBSYSTEM
-	)