MinGW: Compiling Zlib

Zlib is an essential compression library that's required by most open-source software. Download the zlib source and unpack it with unzip or 7zip. Then, compile Zlib like this:

make -f win32/Makefile.gcc

Manually copy the files as follows:

cp -iv zlib1.dll /mingw/bin
cp -iv zconf.h zlib.h /mingw/include
cp -iv libz.a libz.dll.a /mingw/lib

Building 64-bit zlib

Install MinGW64 (as shown in this post). Edit win32/Makefile.gcc so it contains the following lines.

CC=x86_64-w64-mingw32-gcc
RC=x86_64-w64-mingw32-windres

Run the following command to compile 64-bit zlib.

make -f win32/Makefile.gcc

Then, install the files.

make -f win32/Makefile.gcc install BINARY_PATH=/mingw/bin INCLUDE_PATH=/mingw/include LIBRARY_PATH=/mingw/lib SHARED_MODE=1

Importing Official Zlib Build

Normally, you don't have to compile zlib yourself as the official precompiled zlib1.dll is distributed from zlib.net. For convenience, we can just use the precompiled package zlib124-dll.zip from zlib.net. Unpack zlib124-dll.zip to an empty folder. Copy the files to the /mingw tree as follows:

/mingw/bin/zlib1.dll

/mingw/include/zconf.h

/mingw/include/zlib.h

/mingw/lib/zdll.exp

/mingw/lib/zdll.lib

/mingw/lib/zlib.def

To import zlib.dll, we have to create zlib.def.

pexports -h /mingw/include/zlib.h /mingw/bin/zlib1.dll | tr -d '@[:digit:]$' > /mingw/lib/zlib.def

Change to /mingw/lib and create the import library libz.dll.a like this:

cd /mingw/lib
dlltool --def /mingw/lib/zlib.def --dllname zlib1.dll --output-lib /mingw/lib/libz.dll.a

Cross-compile Zlib from Linux

This section describes the steps to cross-compile Zlib for Window from inside Linux. First, install the mingw32-runtime, mingw32-binutils and mingw packages. Create a mingw tree at /opt/mingw:

mkdir /opt/mingw
mkdir /opt/mingw/bin
mkdir /opt/mingw/include
mkdir /opt/mingw/lib

Then, set up the following environment variables:

AR="/usr/bin/i586-mingw32msvc-ar rc"
CC=/usr/bin/i586-mingw32msvc-gcc
CPP=/usr/bin/i586-mingw32msvc-cpp
CPPFLAGS="-I/usr/i586-mingw32msvc/include -I/opt/mingw/include"
CXX=/usr/bin/i586-mingw32msvc-g++
LDFLAGS="-L/usr/i586-mingw32msvc/lib -L/opt/mingw/lib"
PATH=/usr/i586-mingw32msvc/bin:$PATH
RANLIB=/usr/bin/i586-mingw32msvc-ranlib
RC=/usr/bin/i586-mingw32msvc-windres
WINDRES=/usr/bin/i586-mingw32msvc-windres

export AR CC CPP CPPFLAGS CXX LDFLAGS PATH RANLIB RC WINDRES

Then, run the commands below:

/configure --prefix=/opt/mingw
make
make install

At last, create zlib1.dll:

/usr/bin/i586-mingw32msvc-gcc -shared -o /opt/mingw/bin/zlib1.dll -Wl,--out-implib=/opt/mingw/lib/libz.dll.a [!em]*.o