[Qemu-devel] [RfC PATCH] gtk: switch to gtk3 by default, depricate gtk2.

[Gerd Hoffmann <kraxel@redhat.com>]

This patch drops gtk version detection.  gtk3 is used unless you
explicitly ask for gtk2.  Additionally configure prints an error
message in case it finds gtk2 but not gtk3.

Old behavior:
  only gtk3 installed     -- use gtk3
  both gtk2+3 installed   -- use gtk2
  only gtk2 installed     -- use gtk2
  no gtk installed at all -- build without gtk ui

New behavior:
  only gtk3 installed     -- use gtk3
  both gtk2+3 installed   -- use gtk3
  only gtk2 installed     -- error out
  no gtk installed at all -- build without gtk ui

It is still possible to build with gtk2, but you have to explicitly
ask for it using --with-gtkabi=2.0.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 configure | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/configure b/configure
index e9090a0..af49eed 100755
--- a/configure
+++ b/configure
@@ -2154,14 +2154,20 @@ fi
 # GTK probe
 
 if test "$gtkabi" = ""; then
-    # The GTK ABI was not specified explicitly, so try whether 2.0 is available.
-    # Use 3.0 as a fallback if that is available.
-    if $pkg_config --exists "gtk+-2.0 >= 2.18.0"; then
-        gtkabi=2.0
-    elif $pkg_config --exists "gtk+-3.0 >= 3.0.0"; then
-        gtkabi=3.0
-    else
-        gtkabi=2.0
+    gtkabi=3.0
+    if !$pkg_config --exists "gtk+-3.0 >= 3.0.0" &&
+       $pkg_config --exists "gtk+-2.0 >= 2.18.0"; then
+        echo ""
+        echo "ERROR: gtk3 not found, gtk2 is present though."
+        echo ""
+        echo "We strongly recomment to install the gtk3 devel packages and"
+        echo "build qemu with gtk3.  gtk2 support is depricated and will be"
+        echo "dropped (removal scheduled for 2018)."
+        echo ""
+        echo "If it is really your intention to build qemu with gtk2 re-run"
+        echo "configure with --with-gtkabi=2.0."
+        echo ""
+        exit 1
     fi
 fi
 
-- 
1.8.3.1