We don't even define the rule on unsupported platforms.
# alias
lib-all: all
-all: lib libzstd.pc
+all: lib
libzstd.a: ARFLAGS = rcs
libzstd.a: $(ZSTD_OBJ)
#-----------------------------------------------------------------------------
ifneq (,$(filter $(shell uname),Linux Darwin GNU/kFreeBSD GNU OpenBSD FreeBSD NetBSD DragonFly SunOS Haiku))
+all: libzstd.pc
+
DESTDIR ?=
# directory variables : GNU conventions prefer lowercase
# see https://www.gnu.org/prep/standards/html_node/Makefile-Conventions.html