Check for GTK3 if GTK2 is not found.

This is required by the GTK-based enhanced debugger gui.

bochs/CHANGES

@@ -11,8 +11,9 @@ Detailed change log :
   - Implemented AVX512_FP16 Intel instruction set based on softfloat3e library (enabled in Xeon Sapphire Rapids CPU definition)
 
 - Configure and compile
-  - Fixed compilation of debugger with plugins enabled on Windows
+  - Fixed compilation of plugin version with debugger enabled on Windows
   - Removed legacy libltdl code and force using library installed on host system
+  - GTK-based gui debugger can now use GTK3 if GTK2 is not installed
 
 - I/O Devices
   - USB

bochs/configure

@@ -26225,6 +26225,13 @@ if test "$needs_gtk2" = 1; then
         TOOLKIT_CXXFLAGS="`pkg-config --cflags gtk+-2.0`"
         LIBS="$LIBS `pkg-config --libs gtk+-2.0`"
         bx_have_gtk_version=2
+      else
+        pkg-config --exists gtk+-3.0
+        if test x$? = x0; then
+          TOOLKIT_CXXFLAGS="`pkg-config --cflags gtk+-3.0`"
+          LIBS="$LIBS `pkg-config --libs gtk+-3.0`"
+          bx_have_gtk_version=3
+        fi
       fi
     fi
   else

bochs/configure.ac

@@ -2760,6 +2760,13 @@ if test "$needs_gtk2" = 1; then
         TOOLKIT_CXXFLAGS="`pkg-config --cflags gtk+-2.0`"
         LIBS="$LIBS `pkg-config --libs gtk+-2.0`"
         bx_have_gtk_version=2
+      else
+        pkg-config --exists gtk+-3.0
+        if test x$? = x0; then
+          TOOLKIT_CXXFLAGS="`pkg-config --cflags gtk+-3.0`"
+          LIBS="$LIBS `pkg-config --libs gtk+-3.0`"
+          bx_have_gtk_version=3
+        fi
       fi
     fi
   else