diff --git a/toolkit/library/Makefile.in b/toolkit/library/Makefile.in
index 4794c342fab..521e73a8073 100644
--- a/toolkit/library/Makefile.in
+++ b/toolkit/library/Makefile.in
@@ -166,9 +166,12 @@ GARBAGE += \
 endif
 else
 ifdef NS_TRACE_MALLOC
+# In libxul builds, tracemalloc is part of libxul instead.
+ifndef MOZ_ENABLE_LIBXUL
 EXTRA_DSO_LIBS += tracemalloc
 endif
 endif
+endif
 
 ifneq (,$(filter OS2 WINCE WINNT,$(OS_ARCH)))
 SDK_LIBRARY = $(IMPORT_LIBRARY)
diff --git a/toolkit/library/libxul-config.mk b/toolkit/library/libxul-config.mk
index 0a02c8df320..ee51be726d4 100644
--- a/toolkit/library/libxul-config.mk
+++ b/toolkit/library/libxul-config.mk
@@ -339,5 +339,5 @@ EXTRA_DSO_LIBS += boehm
 endif
 
 ifdef NS_TRACE_MALLOC
-EXTRA_DSO_LIBS += tracemalloc
+STATIC_LIBS += tracemalloc
 endif