Use Go modules for building libsyncthing

Requires Go 1.11 or later

.gitignore

@@ -1,5 +1,4 @@
 # C++ objects and libs
-
 *.slo
 *.lo
 *.o
@@ -11,7 +10,6 @@
 *.dylib
 
 # Qt-es
-
 /.qmake.cache
 /.qmake.stash
 *.pro.user
@@ -27,13 +25,15 @@ Makefile*
 *-build-*
 
 # QtCreator
-
 *.autosave
 
-#QtCtreator Qml
+# QtCtreator Qml
 *.qmlproject.user
 *.qmlproject.user.*
 
+# Go modules
+/libsyncthing/go/pkg
+
 # Dolphin
 .directory
 

libsyncthing/CMakeLists.txt

@@ -91,6 +91,7 @@ message(STATUS "Syncthing's go files: ${SRC_FILES_SYNCTHING}")
 # generate Syncthing's assets: don't set GOARCH/GOOS here, this is supposed to run on the host
 add_custom_command(OUTPUT "${SYNCTHING_PATH}/lib/auto/gui.files.go"
                    COMMAND "GOPATH=${GO_DEVELOPMENT_PATH}"
+                           "GO111MODULE=on"
                            "${GO_BIN}"
                            run
                            ./script/genassets.go
@@ -110,6 +111,7 @@ add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libsyncthinginternal.a"
                            "GOOS=${GO_TARGET_OS}"
                            "GOARCH=${GO_TARGET_ARCH}"
                            "CGO_ENABLED=1"
+                           "GO111MODULE=on"
                            "GOPATH=${GO_DEVELOPMENT_PATH}"
                            "${GO_BIN}"
                            build