./Configure
输出：
BS2000-OSD BSD-generic32 BSD-generic64 BSD-ia64 BSD-sparc64 BSD-sparcv8
BSD-x86 BSD-x86-elf BSD-x86_64 Cygwin Cygwin-i386 Cygwin-i486 Cygwin-i586
Cygwin-i686 Cygwin-x86 Cygwin-x86_64 DJGPP MPE/iX-gcc UEFI UWIN VC-CE VC-WIN32
VC-WIN32-ARM VC-WIN32-ONECORE VC-WIN64-ARM VC-WIN64A VC-WIN64A-ONECORE
VC-WIN64A-masm VC-WIN64I aix-cc aix-gcc aix64-cc aix64-gcc android-arm
android-arm64 android-armeabi android-mips android-mips64 android-x86
android-x86_64 android64 android64-aarch64 android64-mips64 android64-x86_64
bsdi-elf-gcc cc darwin-i386-cc darwin-ppc-cc darwin64-arm64-cc darwin64-ppc-cc
darwin64-x86_64-cc gcc haiku-x86 haiku-x86_64 hpux-ia64-cc hpux-ia64-gcc
hpux-parisc-cc hpux-parisc-gcc hpux-parisc1_1-cc hpux-parisc1_1-gcc
hpux64-ia64-cc hpux64-ia64-gcc hpux64-parisc2-cc hpux64-parisc2-gcc hurd-x86
ios-cross ios-xcrun ios64-cross ios64-xcrun iossimulator-xcrun iphoneos-cross
irix-mips3-cc irix-mips3-gcc irix64-mips4-cc irix64-mips4-gcc linux-aarch64
linux-alpha-gcc linux-aout linux-arm64ilp32 linux-armv4 linux-c64xplus
linux-elf linux-generic32 linux-generic64 linux-ia64 linux-mips32 linux-mips64
linux-ppc linux-ppc64 linux-ppc64le linux-sparcv8 linux-sparcv9 linux-x32
linux-x86 linux-x86-clang linux-x86_64 linux-x86_64-clang linux32-s390x
linux64-mips64 linux64-s390x linux64-sparcv9 mingw mingw64 nextstep
nextstep3.3 sco5-cc sco5-gcc solaris-sparcv7-cc solaris-sparcv7-gcc
solaris-sparcv8-cc solaris-sparcv8-gcc solaris-sparcv9-cc solaris-sparcv9-gcc
solaris-x86-gcc solaris64-sparcv9-cc solaris64-sparcv9-gcc solaris64-x86_64-cc
solaris64-x86_64-gcc tru64-alpha-cc tru64-alpha-gcc uClinux-dist
uClinux-dist64 unixware-2.0 unixware-2.1 unixware-7 unixware-7-gcc vms-alpha
vms-alpha-p32 vms-alpha-p64 vms-ia64 vms-ia64-p32 vms-ia64-p64 vos-gcc
vxworks-mips vxworks-ppc405 vxworks-ppc60x vxworks-ppc750 vxworks-ppc750-debug
vxworks-ppc860 vxworks-ppcgen vxworks-simlinux
References
openssl交叉编译问题_ty的专栏-CSDN博客_openssl交叉编译
sudo apt search arm | grep gcc
sudo apt search mips | grep gcc
安装目标平台arm（linux-armv4）交叉编译工具：
sudo apt install -y gcc-arm-linux-gnueabi
生成makefile文件：
./Configure linux-armv4
从O0到O3优化编译命令：
make clean
make -j8 CC=arm-linux-gnueabi-gcc CFLAGS="-Wall -O0" CXXFLAGS="-Wall -O0"
make clean
make -j8 CC=arm-linux-gnueabi-gcc CFLAGS="-Wall -O1" CXXFLAGS="-Wall -O1"
make clean
make -j8 CC=arm-linux-gnueabi-gcc CFLAGS="-Wall -O2" CXXFLAGS="-Wall -O2"
make clean
make -j8 CC=arm-linux-gnueabi-gcc CFLAGS="-Wall -O3" CXXFLAGS="-Wall -O3"
-j8表示同时执行8个编译指令，这个数字一般设置为核心数的两倍。编译完成后可以在apps目录下找到openssl可执行文件。
References
CFLAGS详解_xinyuan510214的专栏-CSDN博客_cflags编写makefile