GTK3 apps using libsoup3 won't start with this message:

GTK+ 2.x symbols detected. Using GTK+ 2.x and GTK+ 3 in the same process is not supported 

Apply equivalent  patch to libsoup3 that was also added libsoup.

--- libsoup-3.6.0/meson.build.old	2024-09-20 13:41:59.904413534 -0400
+++ libsoup-3.6.0/meson.build	2024-09-20 13:43:01.350222270 -0400
@@ -101,14 +101,12 @@
 glib_required_version = '>= 2.70.0'
 glib_dep = dependency('glib-2.0', version : glib_required_version,
                        fallback: ['glib', 'libglib_dep'])
-gmodule_dep = dependency('gmodule-no-export-2.0', version : glib_required_version,
-                         fallback: ['glib', 'libgmodule_dep'])
 gobject_dep = dependency('gobject-2.0', version : glib_required_version,
                        fallback: ['glib', 'libgobject_dep'])
 gio_dep = dependency('gio-2.0', version : glib_required_version,
                        fallback: ['glib', 'libgio_dep'])
 
-glib_deps = [glib_dep, gmodule_dep, gobject_dep, gio_dep]
+glib_deps = [glib_dep, gobject_dep, gio_dep]
 
 cdata = configuration_data()
 
--- libsoup-3.6.0/libsoup/soup-init.c.old	2024-09-20 13:43:42.199169399 -0400
+++ libsoup-3.6.0/libsoup/soup-init.c	2024-09-20 13:45:18.581578208 -0400
@@ -10,7 +10,6 @@
 #endif
 
 #include <glib/gi18n-lib.h>
-#include <gmodule.h>
 #include "gconstructor.h"
 
 #ifdef G_OS_WIN32
@@ -20,21 +19,6 @@
 HMODULE soup_dll;
 #endif
 
-static gboolean
-soup2_is_loaded (void)
-{
-    GModule *module = g_module_open (NULL, 0);
-    gpointer func;
-    gboolean result = FALSE;
-
-    if (g_module_symbol (module, "soup_uri_new", &func))
-        result = TRUE;
-
-    g_module_close (module);
-
-    return result;
-}
-
 static void
 soup_init (void)
 {
@@ -51,8 +35,6 @@
 	bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
 #endif
 
-        if (soup2_is_loaded ())
-                g_error ("libsoup2 symbols detected. Using libsoup2 and libsoup3 in the same process is not supported.");
 }
 
 #if defined (G_OS_WIN32)