separate build cache and actual result, to simplify packaging

Makefile

@@ -1,7 +1,7 @@
 PROJECT_ROOT = $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
 DOCKER_IMAGE ?= lambci/lambda-base-2:build
-TARGET ?=/opt/imagemagick
+TARGET ?=/opt/
 
 MOUNTS = -v $(PROJECT_ROOT):/var/task \
 	-v $(PROJECT_ROOT)result:$(TARGET)

Makefile_ImageMagick

@@ -6,18 +6,20 @@ BZIP2_VERSION ?= 1.0.6
 LIBWEBP_VERSION ?= 0.6.1
 IMAGEMAGICK_VERSION ?= 7.0.8-45
 
-TARGET_DIR ?= /opt/imagemagick
+TARGET_DIR ?= /opt/
+PROJECT_ROOT = $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
+CACHE_DIR=$(PROJECT_ROOT)build/cache
 
 .ONESHELL:
 
-CONFIGURE = PKG_CONFIG_PATH=$(TARGET_DIR)/lib/pkgconfig \
+CONFIGURE = PKG_CONFIG_PATH=$(CACHE_DIR)/lib/pkgconfig \
 	./configure \
-		CPPFLAGS=-I$(TARGET_DIR)/include \
-		LDFLAGS=-L$(TARGET_DIR)/lib \
+		CPPFLAGS=-I$(CACHE_DIR)/include \
+		LDFLAGS=-L$(CACHE_DIR)/lib \
 		--disable-dependency-tracking \
 		--disable-shared \
 		--enable-static \
-		--prefix=$(TARGET_DIR)
+		--prefix=$(CACHE_DIR)
 
 ## libjpg
 
@@ -26,7 +28,7 @@ LIBJPG_SOURCE=jpegsrc.v$(LIBJPG_VERSION).tar.gz
 $(LIBJPG_SOURCE):
 	curl -LO http://ijg.org/files/$(LIBJPG_SOURCE)
 
-$(TARGET_DIR)/lib/libjpeg.a: $(LIBJPG_SOURCE)
+$(CACHE_DIR)/lib/libjpeg.a: $(LIBJPG_SOURCE)
 	tar xf $<
 	cd jpeg*
 	$(CONFIGURE)	 
@@ -41,7 +43,7 @@ LIBPNG_SOURCE=libpng-$(LIBPNG_VERSION).tar.xz
 $(LIBPNG_SOURCE):
 	curl -LO http://prdownloads.sourceforge.net/libpng/$(LIBPNG_SOURCE)
 
-$(TARGET_DIR)/lib/libpng.a: $(LIBPNG_SOURCE)
+$(CACHE_DIR)/lib/libpng.a: $(LIBPNG_SOURCE)
 	tar xf $<
 	cd libpng*
 	$(CONFIGURE)	 
@@ -55,11 +57,11 @@ BZIP2_SOURCE=bzip2-$(BZIP2_VERSION).tar.gz
 $(BZIP2_SOURCE):
 	curl -LO http://prdownloads.sourceforge.net/bzip2/bzip2-$(BZIP2_VERSION).tar.gz
 
-$(TARGET_DIR)/lib/libbz2.a: $(BZIP2_SOURCE)
+$(CACHE_DIR)/lib/libbz2.a: $(BZIP2_SOURCE)
 	tar xf $<
 	cd bzip2-*
 	make libbz2.a
-	make install PREFIX=$(TARGET_DIR)
+	make install PREFIX=$(CACHE_DIR)
 
 # libtiff
 
@@ -68,7 +70,7 @@ LIBTIFF_SOURCE=tiff-$(LIBTIFF_VERSION).tar.gz
 $(LIBTIFF_SOURCE):
 	curl -LO http://download.osgeo.org/libtiff/$(LIBTIFF_SOURCE)
 
-$(TARGET_DIR)/lib/libtiff.a: $(LIBTIFF_SOURCE) $(TARGET_DIR)/lib/libjpeg.a
+$(CACHE_DIR)/lib/libtiff.a: $(LIBTIFF_SOURCE) $(CACHE_DIR)/lib/libjpeg.a
 	tar xf $<
 	cd tiff-*
 	$(CONFIGURE)	 
@@ -82,7 +84,7 @@ LIBWEBP_SOURCE=libwebp-$(LIBWEBP_VERSION).tar.gz
 $(LIBWEBP_SOURCE):
 	curl -L https://github.com/webmproject/libwebp/archive/v$(LIBWEBP_VERSION).tar.gz -o $(LIBWEBP_SOURCE)
 
-$(TARGET_DIR)/lib/libwebp.a: $(LIBWEBP_SOURCE)
+$(CACHE_DIR)/lib/libwebp.a: $(LIBWEBP_SOURCE)
 	tar xf $<
 	cd libwebp-*
 	sh autogen.sh
@@ -98,14 +100,14 @@ $(OPENJP2_SOURCE):
 	curl -L https://github.com/uclouvain/openjpeg/archive/v$(OPENJP2_VERSION).tar.gz -o $(OPENJP2_SOURCE)
 
 
-$(TARGET_DIR)/lib/libopenjp2.a: $(OPENJP2_SOURCE) $(TARGET_DIR)/lib/libpng.a $(TARGET_DIR)/lib/libtiff.a
+$(CACHE_DIR)/lib/libopenjp2.a: $(OPENJP2_SOURCE) $(CACHE_DIR)/lib/libpng.a $(CACHE_DIR)/lib/libtiff.a
 	tar xf $<
 	cd openjpeg-*
 	mkdir -p build
 	cd build 
-	PKG_CONFIG_PATH=$(TARGET_DIR)/lib/pkgconfig cmake .. \
+	PKG_CONFIG_PATH=$(CACHE_DIR)/lib/pkgconfig cmake .. \
 		-DCMAKE_BUILD_TYPE=Release \
-		-DCMAKE_INSTALL_PREFIX=$(TARGET_DIR) \
+		-DCMAKE_INSTALL_PREFIX=$(CACHE_DIR) \
 		-DBUILD_SHARED_LIBS:bool=off \
 		-DBUILD_CODEC:bool=off
 	make clean
@@ -120,27 +122,34 @@ $(IMAGE_MAGICK_SOURCE):
 	curl -L https://github.com/ImageMagick/ImageMagick/archive/$(IMAGEMAGICK_VERSION).tar.gz -o $(IMAGE_MAGICK_SOURCE)
 
 
-LIBS:=$(TARGET_DIR)/lib/libjpeg.a \
-	$(TARGET_DIR)/lib/libpng.a \
-	$(TARGET_DIR)/lib/libopenjp2.a \
-	$(TARGET_DIR)/lib/libtiff.a \
-	$(TARGET_DIR)/lib/libbz2.a \
-	$(TARGET_DIR)/lib/libwebp.a
+LIBS:=$(CACHE_DIR)/lib/libjpeg.a \
+	$(CACHE_DIR)/lib/libpng.a \
+	$(CACHE_DIR)/lib/libopenjp2.a \
+	$(CACHE_DIR)/lib/libtiff.a \
+	$(CACHE_DIR)/lib/libbz2.a \
+	$(CACHE_DIR)/lib/libwebp.a
 
-$(TARGET_DIR)/bin/identify: $(IMAGE_MAGICK_SOURCE) $(LIBS)
+$(CACHE_DIR)/bin/identify: $(IMAGE_MAGICK_SOURCE) $(LIBS)
 	tar xf $<
 	cd ImageMa*
-	$(CONFIGURE) \
-	  --enable-delegate-build \
-	  --without-modules \
-	  --disable-docs \
-	  --without-magick-plus-plus \
-	  --without-perl \
-	  --without-x
+	PKG_CONFIG_PATH=$(CACHE_DIR)/lib/pkgconfig \
+		./configure \
+		CPPFLAGS=-I$(CACHE_DIR)/include \
+		LDFLAGS=-L$(CACHE_DIR)/lib \
+		--disable-dependency-tracking \
+		--disable-shared \
+		--enable-static \
+		--prefix=$(TARGET_DIR) \
+		--enable-delegate-build \
+		--without-modules \
+		--disable-docs \
+		--without-magick-plus-plus \
+		--without-perl \
+		--without-x
 	make clean
 	make all
 	make install
 
 libs: $(LIBS)
 
-all: $(TARGET_DIR)/bin/identify
+all: $(CACHE_DIR)/bin/identify