Android / iOS cross compile example

Android.mk

NICE_PRINT = "\033[1;32m Building $(1)\033[0m\n"

export PREFIX = ${CURDIR}/build/Android/${ARCH}
TOOLCHAIN = toolchain/${ARCH}
LIBDIR = ${PREFIX}/lib
INCLUDEDIR = ${PREFIX}/include

export PATH := $(CURDIR)/${TOOLCHAIN}/bin:${PATH}

export AR=${HOST}-ar
export AS=${HOST}-clang
export CC=${HOST}-clang
export CXX=${HOST}-clang++
export LD=${HOST}-ld
export STRIP=${HOST}-strip

export CFLAGS = -fPIC -O3 -I${INCLUDEDIR}
export CXXFLAGS = -fPIC -O3 -std=c++17 -I${INCLUDEDIR}
export LDFLAGS = -L${LIBDIR}
ifeq ($(ARCH),armeabi-v7a)
export CFLAGS = -fPIC -O3 -march=armv7-a -mfloat-abi=softfp -I${INCLUDEDIR}
export CXXFLAGS = -fPIC -O3 -std=c++17 -march=armv7-a -mfloat-abi=softfp -I${INCLUDEDIR}
export LDFLAGS = -march=armv7-a -Wl,--fix-cortex-a8 -L${LIBDIR}
endif

LDFLAGS_PROTOBUF = -llog
CXXFLAGS_VALHALLA = -DHAS_REMOTE_API=0 -DUSE_OS_TZDB=0 -DINSTALL=. -DMISSING_LEAP_SECONDS=0

# Build separate architectures
all:
	mkdir -p download
	@${MAKE} -f Android.mk arch ARCH=armeabi-v7a HOST=arm-linux-androideabi
	@${MAKE} -f Android.mk arch ARCH=arm64-v8a HOST=aarch64-linux-android >/dev/null
	@${MAKE} -f Android.mk arch ARCH=x86 HOST=i686-linux-android >/dev/null
	@${MAKE} -f Android.mk arch ARCH=x86_64 HOST=x86_64-linux-android >/dev/null

arch: status | ${LIBDIR}/libcurl.a ${LIBDIR}/libsqlite3.a

status:
	@printf $(call NICE_PRINT,$(ARCH)) 1>&2;

include download.mk

${LIBDIR}/libssl.a: download/libressl
	@printf $(call NICE_PRINT,$@) 1>&2;
	cd ${LIBRESSL_DIR} && \
	./configure --host=${HOST} --prefix=${PREFIX} --disable-shared --disable-asm && \
	${MAKE} clean && \
	${MAKE} -j8 install

${LIBDIR}/libcurl.a: download/curl ${LIBDIR}/libssl.a
	@printf $(call NICE_PRINT,$@) 1>&2;
	cd ${CURL_DIR} && \
	./configure --host=${HOST} --prefix=${PREFIX} --disable-shared --with-ssl --disable-verbose --enable-ipv6 --enable-hidden-symbols --enable-threaded-resolver &&\
	${MAKE} clean && \
	${MAKE} -j8 install

AndroidToolchain.mk

NICE_PRINT = "\033[1;32m Building $(1)\033[0m\n"

API=16
API64=21
STL=libc++

all: \
    toolchain/armeabi-v7a \
    toolchain/arm64-v8a \
    toolchain/x86 \
    toolchain/x86_64

toolchain/armeabi-v7a:
	@printf $(call NICE_PRINT,$@) 1>&2;
	@${NDK_PATH}/build/tools/make_standalone_toolchain.py --stl ${STL} --arch arm --api ${API} --install-dir "toolchain/armeabi-v7a"

toolchain/arm64-v8a:
	@printf $(call NICE_PRINT,$@) 1>&2;
	@${NDK_PATH}/build/tools/make_standalone_toolchain.py --stl ${STL} --arch arm64 --api ${API64} --install-dir "toolchain/arm64-v8a"

toolchain/x86:
	@printf $(call NICE_PRINT,$@) 1>&2;
	@${NDK_PATH}/build/tools/make_standalone_toolchain.py --stl ${STL} --arch x86 --api ${API} --install-dir "toolchain/x86"

toolchain/x86_64:
	@printf $(call NICE_PRINT,$@) 1>&2;
	@${NDK_PATH}/build/tools/make_standalone_toolchain.py --stl ${STL} --arch x86_64 --api ${API64} --install-dir "toolchain/x86_64"

clean:
	rm -rf toolchain

download.mk

CURL_VER = 7.61.1
SQLITE3_VER = 3250000
LIBRESSL_VER = 2.8.0

CURL_DIR = download/curl-${CURL_VER}
SQLITE3_DIR = download/sqlite3-${SQLITE3_VER}
LIBRESSL_DIR = download/libressl-${LIBRESSL_VER}

LIB_DIRS = \
	${CURL_DIR} \
	${SQLITE3_DIR} \
	${LIBRESSL_DIR}
  
# Downloading libs
${SQLITE3_DIR}:
	rm -f download/sqlite3

	wget https://www.sqlite.org/2018/sqlite-autoconf-${SQLITE3_VER}.tar.gz
	tar xzvf sqlite-autoconf-${SQLITE3_VER}.tar.gz
	rm sqlite-autoconf-${SQLITE3_VER}.tar.gz
	mv sqlite-autoconf-${SQLITE3_VER} ${SQLITE3_DIR}
	
download/sqlite3: | ${SQLITE3_DIR}
	echo ${SQLITE3_VER} > download/sqlite3
  
${LIBRESSL_DIR}:
	rm -f download/libressl

	wget https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-${LIBRESSL_VER}.tar.gz
	tar xzvf libressl-${LIBRESSL_VER}.tar.gz
	rm libressl-${LIBRESSL_VER}.tar.gz
	mv libressl-${LIBRESSL_VER} ${LIBRESSL_DIR}
	cd ${LIBRESSL_DIR} && patch -p0 < ../../patch/libressl.patch && aclocal && automake && autoconf

download/libressl: | ${LIBRESSL_DIR}
	echo ${LIBRESSL_VER} > download/libressl
  
${CURL_DIR}:
	rm -f download/curl

	wget http://curl.haxx.se/download/curl-${CURL_VER}.tar.gz
	tar xzvf curl-${CURL_VER}.tar.gz
	rm curl-${CURL_VER}.tar.gz
	mv curl-${CURL_VER} ${CURL_DIR}

download/curl: | ${CURL_DIR}
	echo ${CURL_VER} > download/curl

iOS.mk

NICE_PRINT = "\033[1;32m Building $(1)\033[0m\n"

XCODE_TOOLCHAIN = $(shell xcode-select --print-path)/Toolchains/XcodeDefault.xctoolchain
IOS_PLATFORM ?= iphoneos

IOS_SDK = $(shell xcrun -sdk ${IOS_PLATFORM} -show-sdk-path)

export PREFIX = ${CURDIR}/build/iOS/${ARCH}
LIBDIR = ${PREFIX}/lib

export CXX = ${XCODE_TOOLCHAIN}/usr/bin/clang++
export CC = ${XCODE_TOOLCHAIN}/usr/bin/clang
export CFLAGS = -O3 -isysroot ${IOS_SDK} -I${IOS_SDK}/usr/include -arch ${ARCH} -miphoneos-version-min=8.0 -fembed-bitcode -fvisibility=hidden
export CXXFLAGS = ${CFLAGS} -std=c++14 -fno-aligned-allocation -stdlib=libc++ -I${PREFIX}/include
export LDFLAGS = -e _main -stdlib=libc++ -isysroot ${IOS_SDK} -L${LIBDIR} -L${IOS_SDK}/usr/lib -arch ${ARCH} -miphoneos-version-min=8.0
HOST = arm-apple-darwin
LIBTOOLFLAGS = -arch_only ${ARCH}

ifeq ($(ARCH),$(filter $(ARCH),armv7 arm64))
CXXFLAGS += -D__ARM_EABI__=1
CFLAGS += -D__ARM_EABI__=1
endif

# Build separate architectures
all:
	mkdir -p download
	@${MAKE} -f iOS.mk ios_arch ARCH=x86_64 IOS_PLATFORM=iphonesimulator
	@${MAKE} -f iOS.mk ios_arch ARCH=armv7 IOS_PLATFORM=iphoneos >/dev/null
	@${MAKE} -f iOS.mk ios_arch ARCH=arm64 IOS_PLATFORM=iphoneos >/dev/null
	@${MAKE} -f iOS.mk ios_arch ARCH=i386 IOS_PLATFORM=iphonesimulator >/dev/null

ios_arch: status | ${LIBDIR}/libsqlite3.a ${LIBDIR}/libcurl.a

status:
	@printf $(call NICE_PRINT,$(ARCH)) 1>&2;

include download.mk

## Only libs with different settings below
${LIBDIR}/libcurl.a: download/curl
	@printf $(call NICE_PRINT,$@) 1>&2;
	cd ${CURL_DIR} && \
	./configure --host=${HOST} --prefix=${PREFIX} --disable-shared --enable-ipv6 --with-darwinssl --enable-threaded-resolver && \
	${MAKE} clean && \
	${MAKE} -j8 install

libressl.patch

diff -rupN ../libressl-orig/m4/check-os-options.m4 ./m4/check-os-options.m4
--- ../libressl-orig/m4/check-os-options.m4	2018-03-24 17:29:25.000000000 +0300
+++ ./m4/check-os-options.m4	2018-05-23 10:48:09.000000000 +0300
@@ -76,6 +76,12 @@ char buf[1]; getentropy(buf, 1);
 		CPPFLAGS="$CPPFLAGS -D_XOPEN_SOURCE=600 -D__STRICT_ALIGNMENT"
 		AC_SUBST([PLATFORM_LDADD], ['-lpthread'])
 		;;
+	*android*)
+		HOST_OS=linux
+		HOST_ABI=elf
+		CPPFLAGS="$CPPFLAGS -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_SOURCE -D_GNU_SOURCE"
+		AC_SUBST([PLATFORM_LDADD], [])
+		;;
 	*linux*)
 		HOST_OS=linux
 		HOST_ABI=elf

Makefile

all: ios android cleanup

include download.mk

ios:
	@${MAKE} -f iOS.mk

android: android_toolchain
	@${MAKE} -f Android.mk

android_toolchain: 
	@${MAKE} -f AndroidToolchain.mk

clean:
	rm -rf build

clean_all: clean
	rm -rf ${LIB_DIRS}