Use colon (:), not true

These are equivalent, but `:` is a special shell builtin and `true` is
not.

diff --git a/GNUmakefile b/GNUmakefile
index 00b04f2df874acc4a2b517076d9479c973c27687..89a7cf90bbdc7358a0f29d191d6f0d4ea7ee3b7e 100644 (file)
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -203,12 +203,12 @@ XMLTYPES := application/xml text/xml +xml
 ifdef GIT
 ifneq ($(wildcard $(THISDIR)/.git),)
 # A description of the current git revision of ⛩️📰 书社.
-THISREV := $(shell $(CD) $(THISDIR); $(GIT) describe 2> /dev/null || $(GIT) rev-parse HEAD 2> /dev/null || true)
+THISREV := $(shell $(CD) $(THISDIR); $(GIT) describe 2> /dev/null || $(GIT) rev-parse HEAD 2> /dev/null || :)
 endif
 
 ifneq ($(wildcard .git),)
 # A description of the current git revision of the working directory.
-SRCREV := $(shell $(GIT) describe 2> /dev/null || $(GIT) rev-parse HEAD 2> /dev/null || true)
+SRCREV := $(shell $(GIT) describe 2> /dev/null || $(GIT) rev-parse HEAD 2> /dev/null || :)
 endif
 endif
 
@@ -306,7 +306,7 @@ ifeq ($(MODE),urn:fdc:ladys.computer:20231231:Shu1She4:mode:default)
 # Calling this variable is useful when a given target should be updated whenever its list of prerequisites changes in addition to whenever there is a change to one of its prerequisites.
 #
 # ☡ This variable creates at least one subshell every time it is computed.
-override diffprereqs = $(if $(subst $(shell $(CAT) $(call quote,$(BUILDDIR)/lastprereqs/$1) 2> /dev/null || true),,$2),$2 FORCE$(and $(shell $(call ensuredirectory,$(BUILDDIR)/lastprereqs) && $(PRINTF) '%s\n' $(call quote,$2) > $(BUILDDIR)/lastprereqs/$1),),$2)
+override diffprereqs = $(if $(subst $(shell $(CAT) $(call quote,$(BUILDDIR)/lastprereqs/$1) 2> /dev/null || :),,$2),$2 FORCE$(and $(shell $(call ensuredirectory,$(BUILDDIR)/lastprereqs) && $(PRINTF) '%s\n' $(call quote,$2) > $(BUILDDIR)/lastprereqs/$1),),$2)
 
 # (callable) Escape special characters for use in sed regular expressions.
 override sedesc = $(subst /,[/],$(subst $$,\$$,$(subst *,\*,$(subst .,\.,$(subst [,\[,$(subst ^,\^,$(subst \,\\,$1)))))))