Fix prerequisite handling when there are none

[Shushe] / GNUmakefile

diff --git a/GNUmakefile b/GNUmakefile
index f7809ed774f0e01ea81d10fe8a20f857b26664d3..c1b34fc7821285246f689478ff2c29fff8d6bf7b 100644 (file)
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023, 2024 Lady <https://www.ladys.computer/about/#lady>
+# SPDX-FileCopyrightText: 2023, 2024, 2025 Lady <https://www.ladys.computer/about/#lady>
 # SPDX-License-Identifier: MPL-2.0
 
 SHELL = /bin/sh
@@ -275,7 +275,7 @@ export LC_ALL
 
 # Posix timezone information.
 TZ := UTC0
-export UTC0
+export TZ
 
 # The default target for this makefile.
 .DEFAULT_GOAL := all
@@ -354,7 +354,7 @@ override notbuilding := $(and $(filter help clean,$(MAKECMDGOALS)),$(call not,$(
 # If `$(notbuilding)´ is non·empty, this variable produces no result to avoid unnecessary work.
 #
 # ☡ This variable creates at least one subshell every time it is computed.
-override diffprereqs = $(if $(notbuilding),,$(and $(subst $(shell $(CAT) $(call quote,$(BUILDDIR)/lastprereqs/$1) 2>>/dev/null || :),,$2),$(shell $(call ensuredirectory,$(BUILDDIR)/lastprereqs) && $(PRINTF) '%s\n' $(call quote,$2) >|$(BUILDDIR)/lastprereqs/$1),)$2 $(BUILDDIR)/lastprereqs/$1)
+override diffprereqs = $(if $(notbuilding),,$(and $(or $(wildcard $(BUILDDIR)/lastprereqs/$1),$(shell $(TOUCH) $(call quote,$(BUILDDIR)/lastprereqs/$1)),1),$(subst $(shell $(CAT) $(call quote,$(BUILDDIR)/lastprereqs/$1) 2>>/dev/null || :),,$2),$(shell $(call ensuredirectory,$(BUILDDIR)/lastprereqs) && $(PRINTF) '%s\n' $(call quote,$2) >|$(call quote,$(BUILDDIR)/lastprereqs/$1)),)$2 $(BUILDDIR)/lastprereqs/$1)
 
 # ─ ¶ Recipe Variable Definitions ─────────────────────────────────────
 
@@ -746,7 +746,7 @@ else ifeq ($(MODE),urn:fdc:ladys.computer:20231231:Shu1She4:mode:initial)
 # ─ ¶ Non‐Recipe Variable Definitions ─────────────────────────────────
 
 # Non·empty if this is a two‐step build.
-override twostep := $(if $(DATADIR),$(shell if $(TEST) -d $(call quote,$(DATADIR)); then $(PRINTF) '%s\n' '1'; fi),)
+override twostep := $(if $(DATADIR),$(call not,$(shell for dir in $(foreach dir,$(DATADIR),$(call quote,$(dir))); do if $(TEST) '!' -d "$$dir"; then $(PRINTF) '%s\n' '0'; fi; done)),)
 
 # Pair each source magic file with its location in the build directory.
 override magicpair := $(foreach magicfile,$(MAGIC),$(magicfile)|$(BUILDDIR)/magic/$(call namehash,$(magicfile)))
@@ -807,7 +807,7 @@ clean :
 ifneq ($(twostep),)
 # Build the data and remove outdated data files.
 data : $(BUILDDIR)/data.out
-       $(silent)$(FIND) $(call quote,$(BUILDDIR)/data/public) '!' -exec $(GREP) -F -q -x '{}' $(call quote,$<) ';' -a '(' -type d -o -print ')' | $(xargsmultiquote) | $(XARGS) -E '' $(RM)
+       $(silent)$(FIND) $(call quote,$(BUILDDIR)/data/public) '!' '(' -exec $(GREP) -F -q -x '{}' $(call quote,$<) ';' -a -prune ')' -a '(' -type d -o -print ')' | $(xargsmultiquote) | $(XARGS) -E '' $(RM)
 endif
 
 # Provide help.