These are equivalent, but `:` is a special shell builtin and `true` is
not.
ifdef GIT
ifneq ($(wildcard $(THISDIR)/.git),)
# A description of the current git revision of ⛩️📰 书社.
ifdef GIT
ifneq ($(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.
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 || :)
# 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.
# 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)))))))
# (callable) Escape special characters for use in sed regular expressions.
override sedesc = $(subst /,[/],$(subst $$,\$$,$(subst *,\*,$(subst .,\.,$(subst [,\[,$(subst ^,\^,$(subst \,\\,$1)))))))