This is a small suite of scripts and patches to build a musl libc
Prebuilt cross and native compilers are available at
For the impatient,
./build.sh should build a cross compiler to
/opt/cross/<arch>-linux-musl, no muss, no fuss. Otherwise, you can edit
config.sh to make cross-compilers to other architectures, and even copy
config.sh to another directory then run
build.sh from there to avoid polluting
the source dir.
Supported are GCC 4.0.3 until 5.3.0. for newer GCCs check out the musl-cross-make project.
Notes on building normal cross compilers
For ARM, you must set the triple to
eabiis the important bit here)
You can set versions of binutils, GCC or musl in
BINUTILS_VERSION=<version> GCC_VERSION=<version> MUSL_VERSION=<version>
You can set configure flags for each step:
BINUTILS_CONFFLAGS=... GCC_BOOTSTRAP_CONFFLAGS=... MUSL_CONFFLAGS=... GCC_CONFFLAGS=...
You can use a git checkout of musl with:
MUSL_VERSION=<git tag or commit> MUSL_GIT=yes
If you do not have the GMP, MPFR and/or MPC development libraries on your host, you can build them along with GCC with a config.sh line:
If you would like to target a specific CPU revision, usually this is done by GCC configuration options like so:
For ix86 however, it is more common to do this by the target name, e.g.
Upgrading cross compilers
It is possible to upgrade the musl version in a musl-cross cross compiler without rebuilding the entire cross compiler prefix from scratch. Simply download and extract the new version of musl, then configure it like so:
./configure --prefix="<prefix>/<triple>" CC="<triple>-gcc"
<prefix> is the prefix the cross compiler root was installed/extracted
<triple> is the GNU-style target triple (e.g.
Other scripts and helpers
config.shis an example configuration file. In many cases, it will do exactly what you want it to do with no modification, which is why it's simply named
config.shinstead of, e.g.,
extra/build-gcc-deps.shwill build the dependencies for GCC into the build prefix specified by
config.sh, which are just often a nice thing to have. It is of course not necessary.
extra/build-tarballs.shbuilds convenient musl cross-compiler tarballs in a rather inconvenient way. It first builds a musl cross-compiler to the host platform (e.g.
i686), then it uses that to build static cross-compilers to various platforms. As a result, building e.g. three cross-compiler tarballs involves eight compiler build phases (read: this is slow). However, the resultant tarballs are cross-compilers statically linked against musl, making them stable and portable.
config-static.shis an example configuration file for building a static cross-compiler. You can use this if, e.g., you already have a build of musl (and so have
musl-gcc) but would like to make a complete, static cross-compiler based on that, or if you already have a musl cross-compiler (and so have
<arch>-linux-musl-gcc) but would like to make a static cross-compiler itself compiled against musl.
musl-cross depends on:
- shell and coreutils (busybox is fine)
- mercurial or git (for checkout only)
- wget (busybox is fine)
- awk (busybox is fine)
The following are GCC dependencies, which can be installed on the host system,
or installed automatically using
Building GMP additionally requires
Compiler/Arch Compatibility Matrix
* or1k requires integration of a patch (issue #61)