You will find detailed installation instructions in the ECL manual
       https://common-lisp.net/project/ecl/static/manual/pr01s06.html
If you do not have access to the online version, follow the following recipies.

* Unix and similar platforms.
1. Type
   ./configure --help
   to get a list of the flags with which ECL can be configured.
2. Enter
   ./configure ...
   where "..." is the set of flags you have chosen.
3. Use "make" followed by "make install" to build and install ECL.

* Windows with Visual Studio C++ 2008
1. Enter the msvc directory
2. Read the file Makefile to find the configuration options. They
   typically have the form ECL_UNICODE=1, ECL_THREADS=1, etc
3. Enter
   nmake ...
   followed by zero or more of those options
  4. Use "nmake install" to create a directory called "package" with ECL in it.
  5. Move that directory wherever you need.

* Cross-compile for the android platform (from the UNIX machine)
1. Build the host ECL
   #+BEGIN_SRC shell-script
     ./configure ABI=32 CFLAGS="-m32 -g -O2" LDFLAGS="-m32 -g -O2"\
                 --prefix=`pwd`/ecl-android-host --disable-longdouble
     make -j9
     make install
     rm -r build
     export ECL_TO_RUN=`pwd`/ecl-android-host/bin/ecl
   #+END_SRC
2. Configure the toolchain (requires android-ndk) and export the
   necessary paths:
   #+BEGIN_SRC shell-script
     # android-ndk r13b is known to be broken, tested with r9b available at:
     # http://dl.google.com/android/ndk/android-ndk-r9b-linux-x86_64.tar.bz2
     # http://dl.google.com/android/ndk/android-ndk-r9b-darwin-x86_64.tar.bz2
     export NDK_PATH=/opt/android-ndk
     export SYSROOT=${NDK_PATH}/platforms/android-9/arch-arm
     export PATH=${NDK_PATH}/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin:$PATH
  #+END_SRC
3. Build and install the target library
   #+BEGIN_SRC shell-script
     export LDFLAGS="--sysroot=${SYSROOT}"
     export CPPFLAGS="--sysroot=${SYSROOT}"
     ./configure --host=arm-linux-androideabi \
                 --prefix=`pwd`/ecl-android \
                 --with-cross-config=`pwd`/src/util/android.cross_config
     make -j9
     make install
   #+END_SRC
4. Library and assets in the ecl-android directory are ready to run on
   the Android system.

** Building ecl-android on Darwin (OSX)
If your host platform is darwin, then the host compiler should be
built with the Apple's GCC (not the GCC from Macports). Using the
MacPort command:
#+BEGIN_SRC shell-script
  sudo port select --set gcc none
#+END_SRC
   
Hint provided by Pascal J. Bourguignon.