Update tdlib_ping workflow and README to enhance CGO_CFLAGS configuration for building TDLib. Clarify the inclusion of the build directory in the CFLAGS to improve user experience when compiling from source.

.gitea/workflows/tdlib_ping.yaml

@@ -71,8 +71,8 @@ jobs:
           fi
           cd "${ROOT}"
           export CGO_ENABLED=1
-          # Корень клона td-src: там лежит td/telegram/td_json_client.h для #include <td/telegram/...>
-          export CGO_CFLAGS="-I${TDLIB_ROOT}"
+          # Исходники: td/telegram/td_json_client.h; сгенерированные заголовки (tdjson_export.h): build/td/telegram/
+          export CGO_CFLAGS="-I${TDLIB_ROOT} -I${TDLIB_ROOT}/build"
           export CGO_LDFLAGS="-L${DIST} -Wl,-rpath,\$ORIGIN -ltdjson"
           go build -tags=tdlib -trimpath -ldflags="-s -w" -o "${DIST}/${ASSET_BIN}" ./cmd/tdlib_ping
           chmod +x "${DIST}/${ASSET_BIN}"