diff --git a/jdk/make/lib/NioLibraries.gmk b/jdk/make/lib/NioLibraries.gmk
index bc021b14d58..6b7d305f914 100644
--- a/jdk/make/lib/NioLibraries.gmk
+++ b/jdk/make/lib/NioLibraries.gmk
@@ -58,7 +58,10 @@ endif
 ifeq ($(OPENJDK_TARGET_OS), aix)
   BUILD_LIBNIO_MAPFILE:=$(JDK_TOPDIR)/make/mapfiles/libnio/mapfile-$(OPENJDK_TARGET_OS)
   BUILD_LIBNIO_EXFILES += \
-      NativeThread.c
+      /NativeThread.c
+  # Notice: we really need the leading slash here because otherwise every
+  # FILE_NAME in EXCLUDE_FILES will actually match any file ending in FILE_NAME
+  # (e.g. 'NativeThread.c' will also exclude 'AixNativeThread.c').
 endif
 
 $(eval $(call SetupNativeCompilation,BUILD_LIBNIO, \