Install libhal to sysroot too, where it can be found.

Also, add phony target aliases to easily rebuild particular one.

Makefile

@@ -2,6 +2,8 @@ TOP=$(PWD)
 TOOLCHAIN=$(TOP)/xtensa-lx106-elf
 STANDALONE=y
 
+.PHONY: crosstool-NG toolchain libhal
+
 all: sdk_patch $(TOOLCHAIN)/lib/libhal.a $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc
 	@echo
 	@echo "Xtensa toolchain is built, to use it:"
@@ -43,16 +45,20 @@ esp_iot_sdk_v0.9.2/.dir: esp_iot_sdk_v0.9.2_14_10_24.zip
 esp_iot_sdk_v0.9.2_14_10_24.zip:
 	wget --content-disposition "http://bbs.espressif.com/download/file.php?id=9"
 
-$(TOOLCHAIN)/lib/libhal.a: $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc
+libhal: $(TOOLCHAIN)/xtensa-lx106-elf/sysroot/usr/lib/libhal.a
+
+$(TOOLCHAIN)/xtensa-lx106-elf/sysroot/usr/lib/libhal.a: $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc
 	make -C lx106-hal -f ../Makefile _libhal
 
 _libhal:
 	autoreconf -i
-	PATH=$(TOOLCHAIN)/bin:$(PATH) ./configure --host=xtensa-lx106-elf --prefix=$(TOOLCHAIN)
+	PATH=$(TOOLCHAIN)/bin:$(PATH) ./configure --host=xtensa-lx106-elf --prefix=$(TOOLCHAIN)/xtensa-lx106-elf/sysroot/usr
 	PATH=$(TOOLCHAIN)/bin:$(PATH) make
 	PATH=$(TOOLCHAIN)/bin:$(PATH) make install
 
 
+toolchain: $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc
+
 $(TOOLCHAIN)/bin/xtensa-lx106-elf-gcc: crosstool-NG/ct-ng
 	make -C crosstool-NG -f ../Makefile _toolchain
 
@@ -63,6 +69,9 @@ _toolchain:
 	echo CT_STATIC_TOOLCHAIN=y >> .config
 	./ct-ng build
 
+
+crosstool-NG: crosstool-NG/ct-ng
+
 crosstool-NG/ct-ng: crosstool-NG/bootstrap
 	make -C crosstool-NG -f ../Makefile _ct-ng