1 files changed, 17 insertions, 0 deletions
diff --git a/shared.mak b/shared.mak
index c45b2812eb..4e1b62ee99 100644
--- a/shared.mak
+++ b/shared.mak
@@ -53,6 +53,8 @@ ifndef V
 	QUIET          = @
 	QUIET_GEN      = @echo '   ' GEN $@;
 
+	QUIET_MKDIR_P_PARENT  = @echo $(wspfx_SQ) MKDIR -p $(@D);
+
 ## Used in "Makefile"
 	QUIET_CC       = @echo '   ' CC $@;
 	QUIET_AR       = @echo '   ' AR $@;
@@ -84,3 +86,18 @@ ifndef V
 	export V
 endif
 endif
+
+### Templates
+
+## mkdir_p_parent: lazily "mkdir -p" the path needed for a $@
+## file. Uses $(wildcard) to avoid the "mkdir -p" if it's not
+## needed.
+##
+## Is racy, but in a good way; we might redundantly (and safely)
+## "mkdir -p" when running in parallel, but won't need to exhaustively create
+## individual rules for "a" -> "prefix" -> "dir" -> "file" if given a
+## "a/prefix/dir/file". This can instead be inserted at the start of
+## the "a/prefix/dir/file" rule.
+define mkdir_p_parent_template
+$(if $(wildcard $(@D)),,$(QUIET_MKDIR_P_PARENT)$(shell mkdir -p $(@D)))
+endef