Bug 1949346 - Default Gecko shared libraries to no linkage. r=firefox-build-system-reviewers,sergesanspaille

Back in the old days, shared libraries that linked against libxul/xpcom
were common (binary components), but those days are long gone. Even when
GeckoSharedLibrary was added, most uses were linkage=None. Nowadays, all
of them are, it's time to admit that this should be the default.

Differential Revision: https://phabricator.services.mozilla.com/D238899

config/external/gkcodecs/moz.build

@@ -11,7 +11,7 @@
 # both from libxul (when decoding using the codec integration layer Gecko
 # provides) and from ffmpeg (when decoding and encoding through ffmpeg).
 
-GeckoSharedLibrary("gkcodecs", linkage=None)
+GeckoSharedLibrary("gkcodecs")
 SHARED_LIBRARY_NAME = "gkcodecs"
 SYMBOLS_FILE = "gkcodecs.symbols"
 if CONFIG["MOZ_SYSTEM_LIBVPX"]:

config/external/lgpllibs/moz.build

@@ -10,7 +10,7 @@
 #
 # Any library added here should also be reflected in the about:license page.
 
-GeckoSharedLibrary("lgpllibs", linkage=None)
+GeckoSharedLibrary("lgpllibs")
 SHARED_LIBRARY_NAME = "lgpllibs"
 
 # For some reason, mingw builds export way too many symbols.