add basic MacOS X support

Config.in

@@ -119,6 +119,10 @@ config ADK_HOST_NETBSD
 	prompt "NetBSD"
 	boolean
 
+config ADK_HOST_DARWIN
+	prompt "Darwin"
+	boolean
+
 config ADK_HOST_CYGWIN
 	prompt "Cygwin"
 	boolean

mk/build.mk

@@ -270,6 +270,9 @@ endif
 ifeq (${OStype},NetBSD)
 	@echo ADK_HOST_NETBSD=y > $(TOPDIR)/.defconfig
 endif
+ifeq (${OStype},Darwin)
+	@echo ADK_HOST_DARWIN=y > $(TOPDIR)/.defconfig
+endif
 ifneq (,$(filter CYGWIN%,${OStype}))
 	@echo ADK_HOST_CYGWIN=y > $(TOPDIR)/.defconfig
 endif
@@ -278,10 +281,10 @@ endif
 			|grep -i "$(TARGET)"\$$ \
 			|sed -e "s#^config \(.*\)#\1=y#" \
 			 >> $(TOPDIR)/.defconfig; \
-		for symbol in ${DEFCONFIG}; do \
-			echo $$symbol >> $(TOPDIR)/.defconfig; \
-		done; \
 	fi
+	for symbol in ${DEFCONFIG}; do \
+		echo $$symbol >> $(TOPDIR)/.defconfig; \
+	done; \
 	@if [ ! -z "$(FS)" ];then \
 		grep "^config" target/Config.in \
 			|grep -i "$(FS)" \
@@ -338,6 +341,9 @@ endif
 ifeq (${OStype},NetBSD)
 	@echo ADK_HOST_NETBSD=y > $(TOPDIR)/all.config
 endif
+ifeq (${OStype},Darwin)
+	@echo ADK_HOST_DARWIN=y > $(TOPDIR)/all.config
+endif
 ifneq (,$(filter CYGWIN%,${OStype}))
 	@echo ADK_HOST_CYGWIN=y > $(TOPDIR)/all.config
 endif
@@ -346,10 +352,10 @@ endif
 			|grep -i "$(TARGET)"\$$ \
 			|sed -e "s#^config \(.*\)#\1=y#" \
 			>> $(TOPDIR)/all.config; \
-		for symbol in ${DEFCONFIG}; do \
-			echo $$symbol >> $(TOPDIR)/all.config; \
-		done; \
 	fi
+	for symbol in ${DEFCONFIG}; do \
+		echo $$symbol >> $(TOPDIR)/all.config; \
+	done; \
 	@if [ ! -z "$(FS)" ];then \
 		grep "^config" target/Config.in \
 			|grep -i "$(FS)" \