diff --git a/core/cleanspec.mk b/core/cleanspec.mk
index 500ce54f6..4441e2ac3 100644
--- a/core/cleanspec.mk
+++ b/core/cleanspec.mk
@@ -64,6 +64,6 @@ INTERNAL_CLEAN_BUILD_VERSION := 6
 # ************************************************
 
 subdir_cleanspecs := \
-    $(shell build/tools/findleaves.py --prune=$(OUT_DIR) --prune=.repo --prune=.git . CleanSpec.mk)
+    $(shell build/tools/findleaves.py $(FIND_LEAVES_EXCLUDES) . CleanSpec.mk)
 include $(subdir_cleanspecs)
 subdir_cleanspecs :=
diff --git a/core/config.mk b/core/config.mk
index 83295d9be..e32f90181 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -150,6 +150,10 @@ endif
 # are specific to the user's build configuration.
 include $(BUILD_SYSTEM)/envsetup.mk
 
+# Pruned directory options used when using findleaves.py
+# See envsetup.mk for a description of SCAN_EXCLUDE_DIRS
+FIND_LEAVES_EXCLUDES := $(addprefix --prune=, $(OUT_DIR) $(SCAN_EXCLUDE_DIRS) .repo .git)
+
 # The build system exposes several variables for where to find the kernel
 # headers:
 #   TARGET_DEVICE_KERNEL_HEADERS is automatically created for the current
diff --git a/core/definitions.mk b/core/definitions.mk
index b6e5277f4..d90376e2b 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -150,7 +150,7 @@ endef
 # $(1): directory to search under
 # Ignores $(1)/Android.mk
 define first-makefiles-under
-$(shell build/tools/findleaves.py --prune=$(OUT_DIR) --prune=.repo --prune=.git \
+$(shell build/tools/findleaves.py $(FIND_LEAVES_EXCLUDES) \
         --mindepth=2 $(1) Android.mk)
 endef
 
diff --git a/core/envsetup.mk b/core/envsetup.mk
index ee04557e5..bf044553b 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -5,6 +5,11 @@
 # the bottom for the full list
 #     OUT_DIR is also set to "out" if it's not already set.
 #         this allows you to set it to somewhere else if you like
+#     SCAN_EXCLUDE_DIRS is an optional, whitespace separated list of
+#         directories that will also be excluded from full checkout tree
+#         searches for source or make files, in addition to OUT_DIR.
+#         This can be useful if you set OUT_DIR to be a different directory
+#         than other outputs of your build system.
 
 # Set up version information.
 include $(BUILD_SYSTEM)/version_defaults.mk
diff --git a/core/main.mk b/core/main.mk
index 41e280185..e9a5306b2 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -513,7 +513,7 @@ ifneq ($(dont_bother),true)
 # Can't use first-makefiles-under here because
 # --mindepth=2 makes the prunes not work.
 subdir_makefiles := \
-	$(shell build/tools/findleaves.py --prune=$(OUT_DIR) --prune=.repo --prune=.git $(subdirs) Android.mk)
+	$(shell build/tools/findleaves.py $(FIND_LEAVES_EXCLUDES) $(subdirs) Android.mk)
 
 $(foreach mk, $(subdir_makefiles), $(info including $(mk) ...)$(eval include $(mk)))