use source-repo-patch for autoconf issue

experimental_autoconf_flatpak.patch

@@ -1,23 +0,0 @@
-diff --git a/extensions/pref/autoconfig/src/nsReadConfig.cpp b/extensions/pref/autoconfig/src/nsReadConfig.cpp
-index 06f54dd0ab77..54f08ac90104 100644
---- a/extensions/pref/autoconfig/src/nsReadConfig.cpp
-+++ b/extensions/pref/autoconfig/src/nsReadConfig.cpp
-@@ -247,16 +247,8 @@ nsresult nsReadConfig::openAndEvaluateJSFile(const char* aFileName,
-   nsCOMPtr<nsIInputStream> inStr;
-   if (isBinDir) {
-     nsCOMPtr<nsIFile> jsFile;
--#if defined(MOZ_WIDGET_GTK)
--    if (!mozilla::widget::IsRunningUnderFlatpakOrSnap()) {
--#endif  // defined(MOZ_WIDGET_GTK)
--      rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(jsFile));
--#if defined(MOZ_WIDGET_GTK)
--    } else {
--      rv = NS_GetSpecialDirectory(NS_OS_SYSTEM_CONFIG_DIR,
--                                  getter_AddRefs(jsFile));
--    }
--#endif  // defined(MOZ_WIDGET_GTK)
-+    rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(jsFile));
-+
-     if (NS_FAILED(rv)) return rv;
- 
-     rv = jsFile->AppendNative(nsDependentCString(aFileName));

scripts/3_Configure_Source_Code.sh

@@ -174,8 +174,8 @@ patch -Np1 -i "${_PATCHES_DIR}/urlbarprovider-interventions.patch"
 # allow SearchEngines option in non-ESR builds
 patch -Np1 -i "${_PATCHES_DIR}/sed-patches/allow-searchengines-non-esr.patch"
 
-# experimental: allow enabling JPEG XL in non-nightly browser
+# fix broken(?)/unintended handling of autoconf file loading in flatpak/snap environments
-patch -Np1 -i "${CI_PROJECT_DIR}/experimental_autoconf_flatpak.patch"
+patch -Np1 -i "${_PATCHES_DIR}/flatpak_autoconf.patch"
 
 # remove search extensions (experimental)
 # patch -Np1 -i "${_PATCHES_DIR}/search-config.patch"