overhaul build process with litecross, next-gen top-level makefile

.gitignore

@@ -3,4 +3,8 @@
 /output/
 /binutils-*/
 /gcc-*/
-/musl/
+/musl-*/
+/gmp-*/
+/mpc-*/
+/mpfr-*/
+/build-*/

Makefile

@@ -2,154 +2,137 @@
 OUTPUT = $(PWD)/output
 SOURCES = sources
 
+CONFIG_SUB_REV = 3d5db9ebe860
 BINUTILS_VER = 2.25.1
 GCC_VER = 5.2.0
-MUSL_TAG = master
+MUSL_VER = 1.1.14
+GMP_VER = 6.1.0
+MPC_VER = 1.0.3
+MPFR_VER = 3.1.4
 
-GNU_SITE = http://ftp.gnu.org/pub/gnu
+GNU_SITE = https://ftp.gnu.org/pub/gnu
 GCC_SITE = $(GNU_SITE)/gcc
 BINUTILS_SITE = $(GNU_SITE)/binutils
+GMP_SITE = $(GNU_SITE)/gmp
+MPC_SITE = $(GNU_SITE)/mpc
+MPFR_SITE = $(GNU_SITE)/mpfr
 
-COMMON_CONFIG = --disable-werror \
+MUSL_SITE = https://www.musl-libc.org/releases
-	--target=$(TARGET) --prefix=$(OUTPUT) \
+MUSL_REPO = git://git.musl-libc.org/musl
-	--with-sysroot=$(OUTPUT)/$(TARGET)
 
-BINUTILS_CONFIG = $(COMMON_CONFIG)
+BUILD_DIR = build-$(TARGET)
-GCC_CONFIG = $(COMMON_CONFIG) --enable-tls \
-	--disable-libmudflap --disable-libsanitizer
-
-GCC0_VARS = CFLAGS="-O0 -g0" CXXFLAGS="-O0 -g0"
-GCC0_CONFIG = $(GCC_CONFIG) \
-	--with-newlib --disable-libssp --disable-threads \
-	--disable-shared --disable-libgomp --disable-libatomic \
-	--disable-libquadmath --disable-decimal-float --disable-nls \
-	--enable-languages=c
-
-GCC0_BDIR = $(PWD)/gcc-$(GCC_VER)/build0/gcc
-GCC0_CC = $(GCC0_BDIR)/xgcc -B $(GCC0_BDIR)
-
-MUSL_CONFIG = CC="$(GCC0_CC)" --prefix=
 
 -include config.mak
 
-ifeq ($(TARGET),)
+SRC_DIRS = gcc-$(GCC_VER) binutils-$(BINUTILS_VER) musl-$(MUSL_VER) \
-$(error TARGET must be set via config.mak or command line)
+	$(if $(GMP_VER),gmp-$(GMP_VER)) \
-endif
+	$(if $(MPC_VER),mpc-$(MPC_VER)) \
+	$(if $(MPFR_VER),mpfr-$(MPFR_VER))
 
-all: install_binutils install_musl install_gcc
+all:
 
 clean:
-	rm -rf gcc-$(GCC_VER) binutils-$(BINUTILS_VER) musl
+	rm -rf gcc-* binutils-* musl-* gmp-* mpc-* mpfr-* build-*
 
 distclean: clean
 	rm -rf sources
 
-.PHONY: extract_binutils extract_gcc clone_musl
-.PHONY: configure_binutils configure_gcc0 configure_gcc configure_musl
-.PHONY: build_binutils build_gcc0 build_gcc build_musl
-.PHONY: install_binutils install_gcc install_musl
 
-extract_binutils: binutils-$(BINUTILS_VER)/.mcm_extracted
+# Rules for downloading and verifying sources. Treat an external SOURCES path as
-extract_gcc: gcc-$(GCC_VER)/.mcm_extracted
+# immutable and do not try to download anything into it.
-clone_musl: musl/.mcm_cloned
 
-configure_binutils: binutils-$(BINUTILS_VER)/.mcm_configured
+ifeq ($(SOURCES),sources)
-configure_gcc0: gcc-$(GCC_VER)/build0/.mcm_configured
-configure_gcc: gcc-$(GCC_VER)/build/.mcm_configured
-configure_musl: musl/.mcm_configured
-
-build_binutils: binutils-$(BINUTILS_VER)/.mcm_built
-build_gcc0: gcc-$(GCC_VER)/build0/.mcm_built
-build_gcc: gcc-$(GCC_VER)/build/.mcm_built
-build_musl: musl/.mcm_built
-
-install_binutils: binutils-$(BINUTILS_VER)/.mcm_installed
-install_gcc: gcc-$(GCC_VER)/build/.mcm_installed
-install_musl: musl/.mcm_installed
 
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/gmp*)): SITE = $(GMP_SITE)
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/mpc*)): SITE = $(MPC_SITE)
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/mpfr*)): SITE = $(MPFR_SITE)
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/binutils*)): SITE = $(BINUTILS_SITE)
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/gcc*)): SITE = $(GCC_SITE)/$(basename $(basename $(notdir $@)))
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/musl*)): SITE = $(MUSL_SITE)
 
 $(SOURCES):
 	mkdir -p $@
 
 $(SOURCES)/config.sub: | $(SOURCES)
-	wget -O $@ 'http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD'
+	mkdir -p $@.tmp
+	cd $@.tmp && wget -c -O $(notdir $@) "http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=$(CONFIG_SUB_REV)"
+	cd $@.tmp && touch $(notdir $@)
+	cd $@.tmp && sha1sum -c $(PWD)/hashes/$(notdir $@).$(CONFIG_SUB_REV).sha1
+	mv $@.tmp/$(notdir $@) $@
+	rm -rf $@.tmp
 
-$(SOURCES)/binutils-%: | $(SOURCES)
+$(SOURCES)/%: hashes/%.sha1 | $(SOURCES)
-	wget -c -O $@.part $(BINUTILS_SITE)/$(notdir $@)
+	mkdir -p $@.tmp
-	mv $@.part $@
+	cd $@.tmp && wget -c -O $(notdir $@) $(SITE)/$(notdir $@)
+	cd $@.tmp && touch $(notdir $@)
+	cd $@.tmp && sha1sum -c $(PWD)/hashes/$(notdir $@).sha1
+	mv $@.tmp/$(notdir $@) $@
+	rm -rf $@.tmp
 
-$(SOURCES)/gcc-%: | $(SOURCES)
+endif
-	wget -c -O $@.part $(GCC_SITE)/$(basename $(basename $(notdir $@)))/$(notdir $@)
-	mv $@.part $@
 
 
+# Rules for extracting and patching sources, or checking them out from git.
 
-binutils-$(BINUTILS_VER)/.mcm_extracted: $(SOURCES)/binutils-$(BINUTILS_VER).tar.bz2 $(SOURCES)/config.sub
+musl-git-%:
-	tar jxvf $<
+	rm -rf $@.tmp
-	cat patches/binutils-$(BINUTILS_VER)/* | ( cd binutils-$(BINUTILS_VER) && patch -p1 )
+	git clone -b $(patsubst musl-git-%,%,$@) $(MUSL_REPO) $@.tmp
-	cp $(SOURCES)/config.sub binutils-$(BINUTILS_VER)
+	cd $@.tmp && git fsck
-	touch $@
+	mv $@.tmp $@
 
-binutils-$(BINUTILS_VER)/.mcm_configured: binutils-$(BINUTILS_VER)/.mcm_extracted
+%: $(SOURCES)/%.tar.gz | $(SOURCES)/config.sub
-	test -e binutils-$(BINUTILS_VER)/config.status || ( cd binutils-$(BINUTILS_VER) && ./configure $(BINUTILS_CONFIG) )
+	rm -rf $@.tmp
-	touch $@
+	mkdir $@.tmp
+	( cd $@.tmp && tar zxvf - ) < $<
+	test ! -d patches/$@ || cat patches/$@/* | ( cd $@.tmp/$@ && patch -p1 )
+	test ! -f $@.tmp/$@/config.sub || cp -f $(SOURCES)/config.sub $@.tmp/$@
+	rm -rf $@
+	touch $@.tmp/$@
+	mv $@.tmp/$@ $@
+	rm -rf $@.tmp
 
-binutils-$(BINUTILS_VER)/.mcm_built: binutils-$(BINUTILS_VER)/.mcm_configured
+%: $(SOURCES)/%.tar.bz2 | $(SOURCES)/config.sub
-	cd binutils-$(BINUTILS_VER) && $(MAKE)
+	rm -rf $@.tmp
-	touch $@
+	mkdir $@.tmp
-
+	( cd $@.tmp && tar jxvf - ) < $<
-binutils-$(BINUTILS_VER)/.mcm_installed: binutils-$(BINUTILS_VER)/.mcm_built
+	test ! -d patches/$@ || cat patches/$@/* | ( cd $@.tmp/$@ && patch -p1 )
-	cd binutils-$(BINUTILS_VER) && $(MAKE) install
+	test ! -f $@.tmp/$@/config.sub || cp -f $(SOURCES)/config.sub $@.tmp/$@
-	touch $@
+	rm -rf $@
+	touch $@.tmp/$@
+	mv $@.tmp/$@ $@
+	rm -rf $@.tmp
 
 
+# Rules for building.
 
+ifeq ($(TARGET),)
 
-gcc-$(GCC_VER)/.mcm_extracted: $(SOURCES)/gcc-$(GCC_VER).tar.bz2 $(SOURCES)/config.sub
+all:
-	tar jxvf $<
+	@echo TARGET must be set via config.mak or command line.
-	cat patches/gcc-$(GCC_VER)/* | ( cd gcc-$(GCC_VER) && patch -p1 )
+	@exit 1
-	cp $(SOURCES)/config.sub gcc-$(GCC_VER)
-	touch $@
 
-gcc-$(GCC_VER)/build0/.mcm_configured: gcc-$(GCC_VER)/.mcm_extracted | binutils-$(BINUTILS_VER)/.mcm_installed
+else
-	mkdir -p gcc-$(GCC_VER)/build0
-	test -e gcc-$(GCC_VER)/build0/config.status || ( cd gcc-$(GCC_VER)/build0 && $(GCC0_VARS) ../configure $(GCC0_CONFIG) )
-	touch $@
 
-gcc-$(GCC_VER)/build0/.mcm_built: gcc-$(GCC_VER)/build0/.mcm_configured
+$(BUILD_DIR):
-	cd gcc-$(GCC_VER)/build0 && $(MAKE)
+	mkdir -p $@
-	touch $@
 
-gcc-$(GCC_VER)/build/.mcm_configured:  gcc-$(GCC_VER)/.mcm_extracted | binutils-$(BINUTILS_VER)/.mcm_installed musl/.mcm_installed
+$(BUILD_DIR)/Makefile: | $(BUILD_DIR)
-	mkdir -p gcc-$(GCC_VER)/build
+	ln -sf ../litecross/Makefile $@
-	test -e gcc-$(GCC_VER)/build/config.status || ( cd gcc-$(GCC_VER)/build && ../configure $(GCC_CONFIG) )
-	touch $@
 
-gcc-$(GCC_VER)/build/.mcm_built: gcc-$(GCC_VER)/build/.mcm_configured
+$(BUILD_DIR)/config.mak: | $(BUILD_DIR)
-	cd gcc-$(GCC_VER)/build && $(MAKE)
+	printf >$@ -- '%s\n' \
-	touch $@
+	"MUSL_SRCDIR = ../musl-$(MUSL_VER)" \
+	"GCC_SRCDIR = ../gcc-$(GCC_VER)" \
+	"BINUTILS_SRCDIR = ../binutils-$(BINUTILS_VER)" \
+	$(if $(GMP_VER),"GMP_SRCDIR = ../gmp-$(GMP_VER)") \
+	$(if $(MPC_VER),"MPC_SRCDIR = ../mpc-$(MPC_VER)") \
+	$(if $(MPFR_VER),"MPFR_SRCDIR = ../mpfr-$(MPFR_VER)") \
+	"-include ../config.mak"
 
-gcc-$(GCC_VER)/build/.mcm_installed: gcc-$(GCC_VER)/build/.mcm_built
+all: | $(SRC_DIRS) $(BUILD_DIR) $(BUILD_DIR)/Makefile $(BUILD_DIR)/config.mak
-	cd gcc-$(GCC_VER)/build && $(MAKE) install
+	cd $(BUILD_DIR) && $(MAKE) $@
-	touch $@
 
+install: | $(SRC_DIRS) $(BUILD_DIR) $(BUILD_DIR)/Makefile $(BUILD_DIR)/config.mak
+	cd $(BUILD_DIR) && $(MAKE) OUTPUT=$(OUTPUT) $@
 
-
+endif
-
-
-musl/.mcm_cloned:
-	test -d musl || git clone -b $(MUSL_TAG) git://git.musl-libc.org/musl musl
-	touch $@
-
-musl/.mcm_configured: musl/.mcm_cloned gcc-$(GCC_VER)/build0/.mcm_built
-	cd musl && ./configure $(MUSL_CONFIG)
-	touch $@
-
-musl/.mcm_built: musl/.mcm_configured
-	cd musl && $(MAKE) AR=$(OUTPUT)/bin/$(TARGET)-ar RANLIB=$(OUTPUT)/bin/$(TARGET)-ranlib
-	touch $@
-
-musl/.mcm_installed: musl/.mcm_built
-	cd musl && $(MAKE) install DESTDIR=$(OUTPUT)/$(TARGET)
-	ln -sfn . $(OUTPUT)/$(TARGET)/usr
-	touch $@

README.md

@@ -1,17 +1,117 @@
 musl-cross-make
 ===============
 
-This is a quick and simple makefile-based alternative for producing
+This is a the second generation of musl-cross-make, a fast, simple,
-musl-based cross compilers. The current focus is on SH2/J2 Core
+but advanced makefile-based approach for producing musl-targeting
-targets and NOMMU (where PIE or FDPIC is mandatory) since these are
+cross compilers. Features include:
-not adequately supported by other musl cross-compiler toolchain build
-systems, but all musl-supported targets are intended to work.
 
-In addition to the build system, musl-cross-make provides a number of
+- Single-stage GCC build, used to build both musl libc and its own
-patches, including:
+  shared target libs depending on libc.
 
-- Updated versions of the musl target patches going into upstream GCC
+- No hard-coded absoluete paths; resulting cross compilers can be
-- Static-PIE support and optionally defaulting to PIE
+  copied/moved anywhere.
+
+- Ability to build multiple cross compilers for different targets
+  using a single set of patched source trees.
+
+- Nothing is installed until running "make install", and the
+  installation location can be chosen at install time.
+
+- Automatic download of source packages, including GCC prerequisites
+  (GMP, MPC, MPFR), using https and checking hashes.
+
+- Automatic patching with canonical musl support patches and patches
+  which provide bug fixes and features musl depends on for some arch
+  targets.
+
+
+Usage
+-----
+
+The build system can be configured by providing a config.mak file in
+the top-level directory. The only mandatory variable is TARGET, which
+should contain a gcc target tuple (such as i486-linux-musl), but many
+more options are available. See the provided config.mak.dist and
+presets/* for examples.
+
+To compile, run make. To install to $(OUTPUT), run "make install".
+
+The default value for $(OUTPUT) is output; after installing here you
+can move the cross compiler toolchain to another location as desired.
+
+
+
+How it works
+------------
+
+The current musl-cross-make is factored into two layers:
+
+1. The top-level Makefile which is responsible for downloading,
+   verifying, extracting, and patching sources, and for setting up a
+   build directory, and
+
+2. Litecross, the cross compiler build system, which is itself a
+   Makefile symlinked into the build directory.
+
+Most of the real magic takes place in litecross. It begins by setting
+up symlinks to all the source trees provided to it by the caller, then
+builds a combined "src_toolchain" directory of symlinks that combines
+the contents of the top-level gcc and binutils source trees and
+symlinks to gmp, mpc, and mpfr. One configured invocation them
+configures all the GNU toolchain components together in a manner that
+does not require any of them to be installed in order for the others
+to use them.
+
+Rather than building the whole toolchain tree at once, though,
+litecross starts by building just the gcc directory and its
+prerequisites, to get an "xgcc" that can be used to configure musl. It
+then configures musl, installs musl's headers to a staging "build
+sysroot", and builds libgcc.a using those headers. At this point it
+has all the prerequisites to build musl libc.a and libc.so, which the
+rest of the gcc target-libs depend on; once they are built, the full
+toolchain "make all" can proceed.
+
+Litecross does not actually depend on the musl-cross-make top-level
+build system; it can be used with any pre-extracted, properly patched
+set of source trees.
+
+
+Project scope and goals
+-----------------------
+
+The primary goals of this project are to:
+
+- Provide canonical musl support patches for GCC and binutils.
+
+- Serve as a canonical example of how GCC should be built to target
+  musl.
+
+- Streamline the production of musl-targeting cross compilers so that
+  musl users can easily produce musl-linked applications or bootstrap
+  new systems using musl.
+
+- Assist musl and toolchain developers in development and testing.
+
+While the patches applied to GCC and binutils are all intended not to
+break non-musl configurations, musl-cross-make itself is specific to
+musl. Changes to add support for exotic target variants outside of
+what upstream musl supports are probably out-of-scope unless they are
+non-invasive. Changes to fix issues building musl-cross-make to run on
+non-Linux systems are well within scope as long as they are clean.
+
+Most importantly, this is a side project to benefit musl and its
+users. It's not intended to be something high-maintenance or to divert
+development effort away from musl itself.
+
+
+Patches included
+----------------
+
+In addition to canonical musl support patches for GCC,
+musl-cross-make's patch set provides:
+
+- Static-linked PIE support
+- Addition of --enable-default-pie
 - Fixes for SH-specific bugs and bitrot in GCC
 - Support for J2 Core CPU target in GCC & binutils
 - SH/FDPIC ABI support
@@ -22,25 +122,3 @@ build systems, if desired.
 
 Some functionality (SH/FDPIC, and support for J2 specific features) is
 presently only available with gcc 5.2.0 and binutils 2.25.1.
-
-
-Usage
------
-
-The build system make be configured by providing a config.mak file in
-the top-level directory. The only mandatory variable is TARGET, which
-should contain a gcc target tuple (such as sh2eb-linux-musl), but many
-more options are available. The top-level config.mak.dist file shows
-examples, and several full configurations are available in presets/*.
-
-For recent gcc versions that need gmp/mpfr/mpc, suitable versions need
-to be installed in the default library path, or the appropriate --with
-configure options need to be added to GCC_CONFIG in config.mak so that
-the gcc configure process can find them.
-
-After setting up config.mak, simply run make. Parallel builds are
-supported.
-
-The resulting toolchain will be placed ./output by default, or the
-OUTPUT directory specified in config.mak. It is sysrooted and can be
-freely moved to a different location.

config.mak.dist

@@ -1,14 +1,37 @@
-OUTPUT = $(PWD)/output
+#
-TARGET = sh2eb-linux-musl
+# config.mak.dist - sample musl-cross-make configuration
+#
+# Copy to config.mak and edit as desired.
+#
 
-# See the patches directory for supported versions. Versions
+# There is no default TARGET; you must select one here or on the make
-# without patches should not be expected to work until gcc 6.
+# command line. Some examples:
-# Older versions may have known bugs or limited functionality.
 
-BINUTILS_VER = 2.25.1
+# TARGET = i486-linux-musl
-GCC_VER = 5.2.0
+# TARGET = x86_64-linux-musl
+# TARGET = arm-linux-musleabi
+# TARGET = arm-linux-musleabihf
+# TARGET = sh2eb-linux-muslfdpic
+# ...
 
-# Recommended options for faster/simpler build
+# By default, cross compilers are installed to ./output under the top-level
+# musl-cross-make directory and can later be moved wherever you want them.
+# To install directly to a specific location, set it here. Multiple targets
+# can safely be installed in the same location. Some examples:
+
+# OUTPUT = /opt/cross
+# OUTPUT = /usr/local
+
+# By default, latest supported release versions of musl and the toolchain
+# components are used. You can override those here, but the version selected
+# must be supported (under hashes/ and patches/) to work. For musl, you
+# can use "git-refname" (e.g. git-master) instead of a release.
+
+# BINUTILS_VER = 2.25.1
+# GCC_VER = 5.2.0
+# MUSL_VER = git-master
+
+# Recommended options for faster/simpler build:
 
 # COMMON_CONFIG += --disable-nls
 # COMMON_CONFIG += MAKEINFO=/bin/false
@@ -16,17 +39,19 @@ GCC_VER = 5.2.0
 # GCC_CONFIG += --disable-libquadmath --disable-decimal-float
 # GCC_CONFIG += --disable-multilib
 
-# J2/SH2 specific options
+# The following are options needed to make certain targets work right.
+# They may be moved to main build logic rather than config.mak at some
+# point in the future.
 
-# GCC_CONFIG += --with-cpu=mj2
+ifeq ($(TARGET),sh2eb-linux-muslfdpic)
-# GCC_CONFIG += --enable-fdpic
+GCC_CONFIG += --with-cpu=mj2
+GCC_CONFIG += --enable-fdpic
+endif
 
-# Options for using (plain, non-FDPIC) ELF on NOMMU targets
+ifeq ($(TARGET),mips64-linux-musl)
+GCC_CONFIG += --with-abi=64
+endif
 
-# GCC_CONFIG += --enable-default-pie
+ifeq ($(TARGET),arm-linux-musleabihf)
-
+GCC_CONFIG += --with-float=hard
-# Last GPLv2 versions
+endif
-
-# GCC_VER = 4.2.1
-# BINUTILS_VER = 397a64b3
-# BINUTILS_SITE = http://landley.net/aboriginal/mirror

hashes/binutils-2.25.1.tar.bz2.sha1

@@ -0,0 +1 @@
+1d597ae063e3947a5f61e23ceda8aebf78405fcd  binutils-2.25.1.tar.bz2

hashes/binutils-397a64b3.tar.bz2.sha1

@@ -0,0 +1 @@
+f74f1ce2e62c516ba832f99a94289930be7869cf  binutils-397a64b3.tar.bz2

hashes/config.sub.3d5db9ebe860.sha1

@@ -0,0 +1 @@
+7d66e32bb3cce017e1cc9bef59fb6f8271fb7fec  config.sub

hashes/gcc-4.2.1.tar.bz2.sha1

@@ -0,0 +1 @@
+b8a55b13c4e38fae78d5db9a456e2d4ffe003118  gcc-4.2.1.tar.bz2

hashes/gcc-4.7.4.tar.bz2.sha1

@@ -0,0 +1 @@
+f3359a157b3536f289c155363f1736a2c9b414db  gcc-4.7.4.tar.bz2

hashes/gcc-5.2.0.tar.bz2.sha1

@@ -0,0 +1 @@
+fe3f5390949d47054b613edc36c557eb1d51c18e  gcc-5.2.0.tar.bz2

hashes/gmp-6.1.0.tar.bz2.sha1

@@ -0,0 +1 @@
+db38c7b67f8eea9f2e5b8a48d219165b2fdab11f  gmp-6.1.0.tar.bz2

hashes/mpc-1.0.3.tar.gz.sha1

@@ -0,0 +1 @@
+b8be66396c726fdc36ebb0f692ed8a8cca3bcc66  mpc-1.0.3.tar.gz

hashes/mpfr-3.1.4.tar.bz2.sha1

@@ -0,0 +1 @@
+e3b0af77f18505184410d621fe0aae179e229dba  mpfr-3.1.4.tar.bz2

hashes/musl-1.1.14.tar.gz.sha1

@@ -0,0 +1 @@
+b71208e87e66ac959d0e413dd444279d28a7bff1  musl-1.1.14.tar.gz

litecross/Makefile

@@ -0,0 +1,132 @@
+
+OUTPUT = $(PWD)/output
+
+BINUTILS_SRCDIR = BINUTILS_SRCDIR_not_set
+GCC_SRCDIR = GCC_SRCDIR_not_set
+MUSL_SRCDIR = MUSL_SRCDIR_not_set
+
+COMMON_CONFIG = 
+GCC_CONFIG = $(COMMON_CONFIG) 
+TOOLCHAIN_CONFIG = $(GCC_CONFIG)
+
+XGCC_DIR = ../obj_toolchain/gcc
+XGCC = $(XGCC_DIR)/xgcc -B $(XGCC_DIR)
+MUSL_CONFIG = CC="$(XGCC)" LIBCC="../obj_toolchain/$(TARGET)/libgcc/libgcc.a" --prefix=
+
+-include config.mak
+
+FULL_TOOLCHAIN_CONFIG = $(TOOLCHAIN_CONFIG) \
+	--disable-werror \
+	--target=$(TARGET) --prefix= \
+	--with-sysroot=/$(TARGET) \
+	--with-build-sysroot='$$(LC_ROOT)/obj_sysroot' \
+	--enable-tls \
+	--disable-libmudflap --disable-libsanitizer
+
+MUSL_VARS = AR=../obj_toolchain/binutils/ar RANLIB=../obj_toolchain/binutils/ranlib
+
+ifeq ($(TARGET),)
+
+all:
+	@echo TARGET must be set.
+	@exit 1
+
+install: all
+
+else
+
+all: musl toolchain
+
+install: install-musl install-toolchain
+
+musl: obj_musl/.lc_built
+
+toolchain: obj_toolchain/.lc_built
+
+.PHONY: all musl toolchain install-musl install-toolchain clean
+
+src_binutils: | $(BINUTILS_SRCDIR)
+	ln -sf $(BINUTILS_SRCDIR) $@
+
+src_gcc: | $(GCC_SRCDIR)
+	ln -sf $(GCC_SRCDIR) $@
+
+src_musl: | $(MUSL_SRCDIR)
+	ln -sf $(MUSL_SRCDIR) $@
+
+src_gmp: | $(GMP_SRCDIR)
+	ln -sf "$(GMP_SRCDIR)" $@
+
+src_mpc: | $(MPC_SRCDIR)
+	ln -sf "$(MPC_SRCDIR)" $@
+
+src_mpfr: | $(GMP_SRCDIR)
+	ln -sf "$(MPFR_SRCDIR)" $@
+
+src_toolchain: src_binutils src_gcc src_gmp src_mpc src_mpfr
+	rm -rf $@ $@.tmp
+	mkdir $@.tmp
+	cd $@.tmp && ln -sf ../src_binutils/* .
+	cd $@.tmp && ln -sf ../src_gcc/* .
+	cd $@.tmp && ln -sf ../src_gmp gmp
+	cd $@.tmp && ln -sf ../src_mpc mpc
+	cd $@.tmp && ln -sf ../src_mpfr mpfr
+	mv $@.tmp $@
+
+obj_%:
+	mkdir -p $@
+
+obj_sysroot/include:
+	mkdir -p $@
+
+obj_sysroot/usr: | obj_sysroot
+	ln -sf . $@
+
+obj_sysroot/lib64: | obj_sysroot
+	ln -sf lib $@
+
+obj_toolchain/.lc_configured: | obj_toolchain src_toolchain
+	cd obj_toolchain && ../src_toolchain/configure $(FULL_TOOLCHAIN_CONFIG)
+	touch $@
+
+obj_toolchain/gcc/.lc_built: | obj_toolchain/.lc_configured obj_sysroot/usr obj_sysroot/lib64 obj_sysroot/include
+	cd obj_toolchain && $(MAKE) LC_ROOT=$(PWD) all-gcc
+	touch $@
+
+obj_musl/.lc_configured: | obj_toolchain/gcc/.lc_built obj_musl src_musl
+	cd obj_musl && ../src_musl/configure $(MUSL_CONFIG)
+	touch $@
+
+obj_sysroot/.lc_headers: | obj_musl/.lc_configured obj_sysroot
+	cd obj_musl && $(MAKE) DESTDIR=$(PWD)/obj_sysroot install-headers
+	touch $@
+
+obj_toolchain/$(TARGET)/libgcc/.lc_configured: | obj_sysroot/.lc_headers
+	cd obj_toolchain && $(MAKE) LC_ROOT=$(PWD) configure-target-libgcc
+	touch $@
+
+obj_toolchain/$(TARGET)/libgcc/libgcc.a: | obj_toolchain/$(TARGET)/libgcc/.lc_configured
+	cd $(dir $@) && $(MAKE) LC_ROOT=$(PWD) libgcc.a
+
+obj_musl/.lc_built: | obj_toolchain/$(TARGET)/libgcc/libgcc.a
+	cd obj_musl && $(MAKE) $(MUSL_VARS)
+	touch $@
+
+obj_sysroot/.lc_libs: | obj_musl/.lc_built
+	cd obj_musl && $(MAKE) $(MUSL_VARS) DESTDIR=$(PWD)/obj_sysroot install
+	touch $@
+
+obj_toolchain/.lc_built: | obj_toolchain/.lc_configured obj_sysroot/.lc_libs
+	cd obj_toolchain && $(MAKE) LC_ROOT=$(PWD)
+	touch $@
+
+install-musl: | obj_musl/.lc_built
+	cd obj_musl && $(MAKE) $(MUSL_VARS) DESTDIR=$(DESTDIR)$(OUTPUT)/$(TARGET) install
+
+install-toolchain: | obj_toolchain/.lc_built
+	cd obj_toolchain && $(MAKE) LC_ROOT=$(PWD) DESTDIR=$(DESTDIR)$(OUTPUT) install
+
+endif
+
+clean:
+	rm -rf src_* obj_*