Enable building wxGTK without GLX

GLX support was always built with OpenGL since:
d9df7db130 ("Allow choosing between GLX and EGL during run-time", 2025-12-10)

build/cmake/init.cmake

@@ -544,6 +544,10 @@ if(wxUSE_GUI)
                     list(APPEND OPENGL_LIBRARIES ${WAYLANDEGL_LIBRARIES})
                 endif()
             endif()
+            if(X11_FOUND AND OpenGL_GLX_FOUND)
+                # toolkit.cmake calls find_package(X11) if X11 support is needed
+                set(wxHAS_GLX 1)
+            endif()
             if(WXGTK3 AND APPLE AND (NOT wxHAVE_GDK_X11 OR NOT wxHAVE_GDK_WAYLAND))
                 set(OPENGL_FOUND OFF)
             endif()

build/cmake/setup.h.in

@@ -1143,6 +1143,9 @@
 /* Define if you have EGL support */
 #cmakedefine wxHAS_EGL 1
 
+/* Define if you have GLX support */
+#cmakedefine wxHAS_GLX 1
+
 /* Define if you have inotify_xxx() functions. */
 #cmakedefine wxHAS_INOTIFY 1
 

include/wx/glcanvas.h

@@ -18,14 +18,6 @@
 #include "wx/palette.h"
 #include "wx/window.h"
 
-// Most ports have a single implementation of wxGLCanvas, but wxGTK has two:
-// legacy GLX-based one (also used by wxX11) and EGL-based one which is used
-// if support for EGL is available. wxHAS_EGL is defined by the build system
-// but define wxHAS_GLX too for consistency, even if it's always available.
-#if defined(__WXX11__) || defined(__WXGTK__)
-    #define wxHAS_GLX 1
-#endif
-
 class WXDLLIMPEXP_FWD_GL wxGLCanvas;
 class WXDLLIMPEXP_FWD_GL wxGLContext;
 

src/gtk/glcanvas.cpp

@@ -38,6 +38,7 @@ static gboolean draw(GtkWidget* widget, cairo_t* cr, wxGLCanvas* win)
 }
 #endif // __WXGTK3__
 
+#ifdef wxHAS_GLX
 //-----------------------------------------------------------------------------
 // emission hook for "parent-set"
 //-----------------------------------------------------------------------------
@@ -69,6 +70,7 @@ parent_set_hook(GSignalInvocationHint*, guint, const GValue* param_values, void*
     return true;
 }
 }
+#endif // wxHAS_GLX
 
 //---------------------------------------------------------------------------
 // wxGlCanvas
@@ -178,6 +180,7 @@ bool wxGLCanvas::Create(wxWindow *parent,
     if ( !InitVisual(dispAttrs) )
         return false;
 
+#ifdef wxHAS_GLX
     // watch for the "parent-set" signal on m_wxwindow so we can set colormap
     // before m_wxwindow is realized (which will occur before
     // wxWindow::Create() returns if parent is already visible)
@@ -186,6 +189,7 @@ bool wxGLCanvas::Create(wxWindow *parent,
         unsigned sig_id = g_signal_lookup("parent-set", GTK_TYPE_WIDGET);
         g_signal_add_emission_hook(sig_id, 0, parent_set_hook, this, nullptr);
     }
+#endif // wxHAS_GLX
 
     wxWindow::Create( parent, id, pos, size, style, name );
 #ifdef __WXGTK3__

src/unix/glcanvas.cpp

@@ -23,7 +23,9 @@
 #include "wx/glcanvas.h"
 
 #include "wx/unix/private/glcanvas.h"
+#ifdef wxHAS_GLX
 #include "wx/unix/private/glx11.h"
+#endif // wxHAS_GLX
 #ifdef wxHAS_EGL
     #include "wx/unix/private/glegl.h"
 
@@ -229,11 +231,15 @@ wxGLBackend* wxGLBackend::Init()
         return &wxGLBackendEGL::Get();
 #endif // GTK 3 with Wayland
 
+#ifdef wxHAS_GLX
     if ( !(wxGLBackendPreferGLX || wxSystemOptions::IsFalse("opengl.egl")) )
+#endif // wxHAS_GLX
         return &wxGLBackendEGL::Get();
 #endif // wxHAS_EGL
 
+#ifdef wxHAS_GLX
     return &wxGLBackendX11::Get();
+#endif // wxHAS_GLX
 }
 
 wxGLContext::wxGLContext(wxGLCanvas *win,

src/unix/glx11.cpp

@@ -18,7 +18,7 @@
 // for compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
-#if wxUSE_GLCANVAS
+#if wxUSE_GLCANVAS && defined(wxHAS_GLX)
 
 #ifndef WX_PRECOMP
     #include "wx/log.h"