Part 2: Stop building XPCOM base/glue unified.

xpcom/base/moz.build

@@ -92,7 +92,8 @@ SOURCES += [
 ]
 SOURCES['nsDebugImpl.cpp'].no_pgo = True
 
-UNIFIED_SOURCES += [
+# UNIFIED_SOURCES += [
+SOURCES += [
     'AvailableMemoryTracker.cpp',
     'ClearOnShutdown.cpp',
     'CycleCollectedJSRuntime.cpp',

xpcom/glue/moz.build

@@ -86,10 +86,10 @@ EXPORTS.mozilla.threads += [
 
 include('objs.mozbuild')
 
-UNIFIED_SOURCES += xpcom_gluens_src_cppsrcs
-UNIFIED_SOURCES += xpcom_glue_src_cppsrcs
+SOURCES += xpcom_gluens_src_cppsrcs
+SOURCES += xpcom_glue_src_cppsrcs
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'GenericModule.cpp',
     'nsStringAPI.cpp',
 ]