Heatshrink CLI tool fails to compile on Linux Mint 18.3 VM with x86_64 GCC 5.4

I git cloned your repo, changed directory to esphttpd/lib/heatshrink and ran make heatshrink.

GCC info:

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 5.4.0-6ubuntu1~16.04.9' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs --enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-5 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9)

The actual error:

heatshrink.c: In function ‘proc_args’:
heatshrink.c:388:17: warning: implicit declaration of function ‘getopt’ [-Wimplicit-function-declaration]
     while ((a = getopt(argc, argv, "hedi:w:l:v")) != -1) {
                 ^
heatshrink.c:397:51: error: ‘optarg’ undeclared (first use in this function)
             cfg->decoder_input_buffer_size = atoi(optarg);
                                                   ^
heatshrink.c:397:51: note: each undeclared identifier is reported only once for each function it appears in
heatshrink.c:413:13: error: ‘optind’ undeclared (first use in this function)
     argc -= optind;
             ^
make: *** [heatshrink] Error 1

cc -std=c99 -g -Wall -Wextra -pedantic  -O3 -Wmissing-prototypes -Wstrict-prototypes -Wmissing-declarations    heatshrink.c heatshrink_encoder.o heatshrink_decoder.o   -o heatshrink
<builtin>: recipe for target 'heatshrink' failed

I'd like to use this library on my ESP8266/ESP32 based feather board(s). However, if I can't use the command line tool to compress the files, I'm kinda stuck.

mziwisky / esp8266-dev

Heatshrink CLI tool fails to compile on Linux Mint 18.3 VM with x86_64 GCC 5.4 #8