How to compile glibc 32bit on an x86_64 machine

Question

I\'m trying to compile glibc (as a secondary, not a system replacement) 2.6 on an x86_64, and trying to get it to produce 32-bit objects. When I give it a standard configure

Answer 1

The following works for me:

../../src/glibc-2.6/configure --prefix=$HOME/glibc32-2.6 \
 CC="gcc -m32" CXX="g++ -m32" i686-linux-gnu

Answer 2

Three important ./configure flags:

• --build= The system performing the build. Looks like yours is x86_64-pc-linux-gnu.
• --host= The system on which the generated objects will be used. You want to set this to i386-pc-linux-gnu.
• --target= If you are building a compiler, the system for which the built compiler will generate objects.

To perform a cross-compile, you must specify both --build= and --host=. When you only specify --host=, it will still attempt to build a native (x86_64) glibc.

Answer 3

I edited the question, but then I realized the proper way is to add an answer. Here's what finally worked:

 $ ../../src/glibc-2.6/configure --prefix=$HOME/glibc32-2.6 \
     --host=i686-linux-gnu \
     --build=i686-linux-gnu \
     CC="gcc -m32" CXX="g++ -m32" \
     CFLAGS="-O2 -march=i686" \
     CXXFLAGS="-O2 -march=i686"

I think putting -m32 in CC and CXX instead of CFLAGS and CXXFLAGS was important because there was at least one compile operation during the make which didn't use CFLAGS or CXXFLAGS, and -m32 absolutely has to always be there. Not sure why -march=i686 was necessary (given the -m32 parts and the --host/build options), but it was.