build: fix out-of-tree builds

[notmuch] / Makefile

diff --git a/Makefile b/Makefile
index 73a85546948fc71df0002adb1257c13aa248fc5b..0428160b80c23c5e65900b7c9a346508550bc85e 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -2,9 +2,10 @@
 # given explicitly on the command line) so mention it first.
 all:
 
-# List all subdirectories here. Each contains its own Makefile.local
-subdirs := compat completion emacs lib man parse-time-string
-subdirs += performance-test util test
+# List all subdirectories here. Each contains its own Makefile.local.
+# Use of '=', without '+=', seems to be required for out-of-tree
+# builds to work.
+subdirs = compat completion emacs lib man parse-time-string performance-test util test
 
 # We make all targets depend on the Makefiles themselves.
 global_deps = Makefile Makefile.config Makefile.local \