[vte] build: Bump gtk min-req version to 3.4

[Egmont Koblinger <egmontkob src gnome org>]

commit 537fbfa2c197d3273c2630920ed452284f2a8ff5
Author: Egmont Koblinger <egmont gmail com>
Date:   Wed Sep 18 14:15:52 2019 +0200

    build: Bump gtk min-req version to 3.4
    
    https://gitlab.gnome.org/GNOME/vte/issues/172

 meson.build   |  2 +-
 src/reflect.c | 11 ++++++-----
 2 files changed, 7 insertions(+), 6 deletions(-)
---
diff --git a/meson.build b/meson.build
index faf41202..ca613d93 100644
--- a/meson.build
+++ b/meson.build
@@ -32,7 +32,7 @@ project(
 # Requirements
 
 gtk3_req_version          = '3.20.0'
-gtk3_min_req_version      = '3.0'
+gtk3_min_req_version      = '3.4'
 gtk3_max_allowed_version  = '3.20'
 gtk4_req_version          = '4.0.0'
 
diff --git a/src/reflect.c b/src/reflect.c
index 83c34696..beb658c5 100644
--- a/src/reflect.c
+++ b/src/reflect.c
@@ -48,7 +48,7 @@ terminal_shell_text_view(GtkWidget *widget)
 static GtkAdjustment *
 terminal_adjustment_text_view(GtkWidget *terminal)
 {
-       return gtk_text_view_get_vadjustment(GTK_TEXT_VIEW(terminal));
+        return gtk_scrollable_get_vadjustment(GTK_SCROLLABLE(terminal));
 }
 #endif
 #ifdef USE_VTE
@@ -260,13 +260,14 @@ main(int argc, char **argv)
                                       GTK_POLICY_AUTOMATIC);
        gtk_container_add(GTK_CONTAINER(tophalf), terminal);
 #else
-       tophalf = gtk_hbox_new(FALSE, 0);
+        tophalf = gtk_grid_new();
 
-       gtk_box_pack_start(GTK_BOX(tophalf), terminal, TRUE, TRUE, 0);
+        gtk_grid_attach(GTK_GRID(tophalf), terminal, 0, 0, 1, 1);
        gtk_widget_show(terminal);
 
-       GtkWidget* scrollbar = gtk_vscrollbar_new(terminal_adjustment(terminal));
-       gtk_box_pack_start(GTK_BOX(tophalf), scrollbar, FALSE, TRUE, 0);
+        GtkWidget* scrollbar = gtk_scrollbar_new(GTK_ORIENTATION_VERTICAL,
+                                                 terminal_adjustment(terminal));
+        gtk_grid_attach(GTK_GRID(tophalf), scrollbar, 1, 0, 1, 1);
        gtk_widget_show(scrollbar);
 #endif
        gtk_widget_show(terminal);