Enable multiple DATADIR

⛩📰 书社 requires that `$(DATADIR)` point to at least one real
directory before entering two‐step mode, but it failed to correctly
handle this check in the case where there were multiple `$(DATADIR)`
supplied.

diff --git a/GNUmakefile b/GNUmakefile
index 563426489af0e78109b07d1b5316cdd18e8f1f56..3ee32a5edf55de9ce7188951e9fdfd642e6ed075 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
@@ -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)))