add support for installation of linux kernel headers

this feature is still experimental and requires manually setting a
LINUX_ARCH make variable matching the target. automatic mapping will
be added later. if LINUX_ARCH is not set, header installation is
skipped.

.gitignore

@@ -8,3 +8,4 @@
 /mpc-*/
 /mpfr-*/
 /build-*/
+/linux-*/

Makefile

@@ -9,6 +9,7 @@ MUSL_VER = 1.1.14
 GMP_VER = 6.1.0
 MPC_VER = 1.0.3
 MPFR_VER = 3.1.4
+LINUX_VER = 4.4.10
 
 GNU_SITE = https://ftp.gnu.org/pub/gnu
 GCC_SITE = $(GNU_SITE)/gcc
@@ -20,6 +21,8 @@ MPFR_SITE = $(GNU_SITE)/mpfr
 MUSL_SITE = https://www.musl-libc.org/releases
 MUSL_REPO = git://git.musl-libc.org/musl
 
+LINUX_SITE = https://cdn.kernel.org/pub/linux/kernel
+
 BUILD_DIR = build-$(TARGET)
 
 -include config.mak
@@ -27,7 +30,8 @@ BUILD_DIR = build-$(TARGET)
 SRC_DIRS = gcc-$(GCC_VER) binutils-$(BINUTILS_VER) musl-$(MUSL_VER) \
 	$(if $(GMP_VER),gmp-$(GMP_VER)) \
 	$(if $(MPC_VER),mpc-$(MPC_VER)) \
-	$(if $(MPFR_VER),mpfr-$(MPFR_VER))
+	$(if $(MPFR_VER),mpfr-$(MPFR_VER)) \
+	$(if $(LINUX_VER),linux-$(LINUX_VER))
 
 all:
 
@@ -49,6 +53,7 @@ $(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/mpfr*)): SITE = $(MPFR_S
 $(patsubst hashes/%.sha1,$(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 = $(MUSL_SITE)
+$(patsubst hashes/%.sha1,$(SOURCES)/%,$(wildcard hashes/linux*)): SITE = $(LINUX_SITE)/v$(patsubst linux-%,%,$(basename $(basename $(basename $(basename $(notdir $@)))))).x
 
 $(SOURCES):
 	mkdir -p $@
@@ -102,6 +107,17 @@ musl-git-%:
 	mv $@.tmp/$@ $@
 	rm -rf $@.tmp
 
+%: $(SOURCES)/%.tar.xz | $(SOURCES)/config.sub
+	rm -rf $@.tmp
+	mkdir $@.tmp
+	( cd $@.tmp && tar Jxvf - ) < $<
+	test ! -d patches/$@ || 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
+
 
 # Rules for building.
 
@@ -127,6 +143,7 @@ $(BUILD_DIR)/config.mak: | $(BUILD_DIR)
 	$(if $(GMP_VER),"GMP_SRCDIR = ../gmp-$(GMP_VER)") \
 	$(if $(MPC_VER),"MPC_SRCDIR = ../mpc-$(MPC_VER)") \
 	$(if $(MPFR_VER),"MPFR_SRCDIR = ../mpfr-$(MPFR_VER)") \
+	$(if $(LINUX_VER),"LINUX_SRCDIR = ../linux-$(LINUX_VER)") \
 	"-include ../config.mak"
 
 all: | $(SRC_DIRS) $(BUILD_DIR) $(BUILD_DIR)/Makefile $(BUILD_DIR)/config.mak

hashes/linux-4.4.10.tar.xz.sha1

@@ -0,0 +1 @@
+03b45399a93ae8bc18f1f27ad72f3e98c6bba5c8  linux-4.4.10.tar.xz

litecross/Makefile

@@ -156,6 +156,29 @@ install-toolchain: | obj_toolchain/.lc_built
 	cd obj_toolchain && $(MAKE) MAKE="$(MAKE)" LC_ROOT=$(PWD) DESTDIR=$(DESTDIR)$(OUTPUT) install
 	ln -sf $(TARGET)-gcc $(DESTDIR)$(OUTPUT)/bin/$(TARGET)-cc
 
+ifneq ($(LINUX_SRCDIR),)
+ifneq ($(LINUX_ARCH),)
+all: kernel-headers
+install: install-kernel-headers
+kernel-headers: | obj_kernel_headers
+src_kernel_headers: | $(LINUX_SRCDIR)
+	mkdir -p $@.tmp/arch/$(LINUX_ARCH)
+	cp -R $(LINUX_SRCDIR)/arch/$(LINUX_ARCH)/include $@.tmp/arch/$(LINUX_ARCH)
+	cp -R $(LINUX_SRCDIR)/arch/$(LINUX_ARCH)/Makefile $@.tmp/arch/$(LINUX_ARCH)
+	cp -R $(LINUX_SRCDIR)/include $@.tmp
+	cp -R $(LINUX_SRCDIR)/scripts $@.tmp
+	cp -R $(LINUX_SRCDIR)/Makefile $@.tmp
+	mv $@.tmp $@
+obj_kernel_headers: | src_kernel_headers
+	rm -rf $@.tmp
+	cd src_kernel_headers && $(MAKE) ARCH=$(LINUX_ARCH) INSTALL_HDR_PATH=$(PWD)/$@.tmp headers_install
+	mv $@.tmp $@
+install-kernel-headers: | obj_kernel_headers
+	mkdir -p $(DESTDIR)$(OUTPUT)$(SYSROOT)/include
+	cp -R obj_kernel_headers/include/* $(DESTDIR)$(OUTPUT)$(SYSROOT)/include
+endif
+endif
+
 endif
 
 clean: