Instead of hard-coding GOBJECT_INTROSPECTION_LIBDIR when
gobject-introspection is built, use dladdr() to determine where
GOBJECT_INTROSPECTION_LIBDIR is and use that path to calculate the
repository directory.

This fixes gobject-introspection-native accessing paths across build
directories (e.g. if the build directories use the same shared state
cache or sstate mirror).

diff --git a/girepository/girepository.c b/girepository/girepository.c
index c1fa3d3..efa557e 100644
--- a/girepository/girepository.c
+++ b/girepository/girepository.c
@@ -38,6 +40,8 @@
 #include "gitypelib-internal.h"
 #include "girepository-private.h"
 
+#include <dlfcn.h>
+
 /**
  * GIRepository:
  *
@@ -260,7 +264,13 @@ gi_repository_get_libdir (void)
           libdir = GOBJECT_INTROSPECTION_LIBDIR;
         }
 #else /* !G_PLATFORM_WIN32 && !__APPLE__ */
-        libdir = GOBJECT_INTROSPECTION_LIBDIR;
+        Dl_info gi_lib_info;
+        if (dladdr (gi_repository_get_version, &gi_lib_info)) {
+          libdir = g_path_get_dirname (gi_lib_info.dli_fname);
+          g_ignore_leak (libdir);
+        } else {
+          libdir = GOBJECT_INTROSPECTION_LIBDIR;
+        }
 #endif
       g_once_init_leave_pointer (&static_libdir, libdir);
     }
diff --git a/girepository/meson.build b/girepository/meson.build
index 6a8c5b5..8892f2a 100644
--- a/girepository/meson.build
+++ b/girepository/meson.build
@@ -139,7 +139,7 @@ libgirepository_internals = static_libra
   c_args: gir_c_args + custom_c_args,
   gnu_symbol_visibility : 'hidden',
   include_directories : [configinc, girepoinc],
-  dependencies: [girepo_gthash_dep, libffi_dep],
+  dependencies: [girepo_gthash_dep, libffi_dep, cc.find_library('dl')],
 )
 
 libgirepository_internals_dep = declare_dependency(
diff -rup glib-2.84.0/girepository/tests/repository-search-paths.c.orig glib-2.84.0/girepository/tests/repository-search-paths.c
--- a/girepository/tests/repository-search-paths.c
+++ a/girepository/tests/repository-search-paths.c
@@ -28,7 +28,7 @@ test_repository_search_paths_get_expecte
 #if defined(G_PLATFORM_WIN32)
   const char *tests_build_dir = g_getenv ("G_TEST_BUILDDIR");
   char *expected_rel_path = g_build_filename (tests_build_dir, "lib", "girepository-1.0", NULL);
-#elif defined(__APPLE__)
+#elif defined(__APPLE__) || 1
   const char *tests_build_dir = g_getenv ("G_TEST_BUILDDIR");
   char *expected_rel_path = g_build_filename (tests_build_dir, "..", "girepository-1.0", NULL);
 #else /* !G_PLATFORM_WIN32 && !__APPLE__ */