Makefile: build 32-bit binary on armv8l (#3434)

armv8l is always 32-bit and should implement the armv7 ISA, so
just use the same filename as for armv7.

This avoids wrongly building a 64-bit binary because of an incorrect assumption
of what 'armv8l' is (a 32-bit system).

Obviously, we should not then build a 64-bit (arm64) binary. Especially
given armv8l is often used in arm32-on-arm64 chroots to build stuff for
weaker-powered arm32 devices.

Signed-off-by: Sam James <sam@gentoo.org>

Makefile

@@ -57,7 +57,9 @@ else ifeq ($(UNAME_M),armv6l)
 else ifeq ($(UNAME_M),armv7l)
 	BINARY := $(BINARYARM7)
 else ifeq ($(UNAME_M),armv8l)
-	BINARY := $(BINARYARM8)
+	# armv8l is always 32-bit and should implement the armv7 ISA, so
+	# just use the same filename as for armv7.
+	BINARY := $(BINARYARM7)
 else ifeq ($(UNAME_M),arm64)
 	BINARY := $(BINARYARM8)
 else ifeq ($(UNAME_M),aarch64)