engine: move our HTTP client to http subfolder, prepare for curl integration

engine/wscript

@@ -33,6 +33,15 @@ int main(int argc, char **argv)
 }
 '''
 
+CURL_CHECK_FRAGMENT='''
+#include <curl/curl.h>
+int main(int argc, char **argv)
+{
+	CURL *easy = curl_easy_init();
+	return 0;
+}
+'''
+
 def options(opt):
 	grp = opt.add_option_group('Engine options')
 
@@ -60,6 +69,9 @@ def options(opt):
 	grp.add_option('--enable-ffmpeg-dlopen', action = 'store_true', dest = 'FFMPEG_DLOPEN', default = False,
 		help = 'load ffmpeg libraries in runtime [default: %(default)s]')
 
+	grp.add_option('--disable-curl', action = 'store_false', dest = 'CURL', default = False,
+		help = 'enable curl-based HTTP downloader [default: %(default)s]')
+
 	opt.load('sdl2')
 
 def find_sdl(conf):
@@ -163,6 +175,19 @@ def configure(conf):
 		conf.define('HAVE_FFMPEG', True)
 		conf.define_cond('XASH_FFMPEG_DLOPEN', conf.options.FFMPEG_DLOPEN)
 
+	if conf.options.CURL:
+		pkgconf_args = '--cflags --libs'
+		features = 'c cprogram'
+
+		# TODO: when dlopen curl is implemented, we might not need this check
+		# as we can safely bundle curl headers as curl never breaks API/ABI
+		conf.check_cfg(package='libcurl', uselib_store='CURL', args=pkgconf_args)
+
+		conf.check(features=features, fragment=CURL_CHECK_FRAGMENT, use='CURL', msg='Checking for curl sanity')
+
+		conf.env.CURL=True
+		conf.define('HAVE_CURL', True)
+
 	conf.define_cond('XASH_STATIC_LIBS', conf.env.STATIC_LINKING)
 	conf.define_cond('XASH_CUSTOM_SWAP', conf.options.CUSTOM_SWAP)
 	conf.define_cond('XASH_NO_ASYNC_NS_RESOLVE', not have_async_resolve)
@@ -199,6 +224,12 @@ def build(bld):
 	if bld.get_define('XASH_STATIC_LIBS'):
 		source += ['platform/misc/lib_static.c']
 
+	if bld.get_define('HAVE_CURL'):
+		source += ['common/http/net_http_curl.c']
+		libs += ['CURL']
+	else:
+		source += ['common/http/net_http_xash.c']
+
 	if bld.env.DEST_OS == 'win32':
 		libs += ['USER32', 'SHELL32', 'GDI32', 'ADVAPI32', 'DBGHELP', 'PSAPI', 'WS2_32']
 	elif bld.env.DEST_OS == 'nswitch':