openwrt: Add option to enable bitmain driver

openwrt/bfgminer/Makefile

@@ -62,6 +62,10 @@ config PACKAGE_$(PKG_NAME)_libusb
 	bool "Build with libusb support (Cointerra, HashBuster Micro, Klondike, X6500 & ZTEX)"
 	depends on PACKAGE_$(PKG_NAME)
 	default y
+config PACKAGE_$(PKG_NAME)_bitmain
+	bool "Build with bitmain driver (only for S* series miners)"
+	depends on PACKAGE_$(PKG_NAME)
+	default n
 config PACKAGE_$(PKG_NAME)_keccak
 	bool "Build with Keccak algorithm support"
 	depends on PACKAGE_$(PKG_NAME)
@@ -94,6 +98,10 @@ ifndef CONFIG_PACKAGE_$(PKG_NAME)_libusb
 CONFIGURE_ARGS += --without-libusb
 endif
 
+ifndef CONFIG_PACKAGE_$(PKG_NAME)_bitmain
+CONFIGURE_ARGS += --enable-bitmain
+endif
+
 ifdef CONFIG_PACKAGE_$(PKG_NAME)_keccak
 CONFIGURE_ARGS += --enable-keccak
 endif