Add support to arm64 arch (#27)

Author: tak30

c_src/Makefile

@@ -11,15 +11,21 @@ ERL_INTERFACE_LIB_DIR ?= $(shell erl -noshell -eval "io:format(\"~ts\", [code:li
 
 C_SRC_DIR = $(CURDIR)
 C_SRC_OUTPUT ?= $(CURDIR)/../priv/$(PROJECT).so
+UNAME_ARCH := $(shell uname -m)
 
 # System type and C compiler/flags.
 
 UNAME_SYS := $(shell uname -s)
 ifeq ($(UNAME_SYS), Darwin)
+	ifeq ($(UNAME_ARCH), arm64)
+		ARCH := arm64
+	else
+		ARCH := x86_64
+	endif
 	CC ?= cc
-	CFLAGS ?= -O3 -std=c99 -arch x86_64 -Wall -Wmissing-prototypes
-	CXXFLAGS ?= -O3 -arch x86_64 -finline-functions -Wall
-	LDFLAGS ?= -arch x86_64 -flat_namespace -undefined suppress
+	CFLAGS ?= -O3 -std=c99 -arch $(ARCH) -Wall -Wmissing-prototypes
+	CXXFLAGS ?= -O3 -arch $(ARCH) -finline-functions -Wall
+	LDFLAGS ?= -arch $(ARCH) -flat_namespace -undefined suppress
 else ifeq ($(UNAME_SYS), FreeBSD)
 	CC ?= cc
 	CFLAGS ?= -O3 -std=c99 -Wall -Wmissing-prototypes