"fatal error: bits/libc-header-start.h: No such file or directory" while compiling HTK

The -m32 is telling gcc to compile for a 32-bit platform. On a 64-bit machine, gcc normally only comes with 64-bit libraries. You have two options:

1. Install 32-bit headers and libraries. Here's how you'd do this on Ubuntu: https://askubuntu.com/questions/91909/trouble-compiling-a-32-bit-binary-on-a-64-bit-machine

2. Compile for 64-bit instead. Modify this line in the file named configure:

   CFLAGS="-m32 -ansi -D_SVID_SOURCE -DOSS_AUDIO -D'ARCH=\"$host_cpu\"' $CFLAGS"
   

   Delete -m32, giving you:

   CFLAGS="-ansi -D_SVID_SOURCE -DOSS_AUDIO -D'ARCH=\"$host_cpu\"' $CFLAGS"
   

   Run ./configure, then make clean, then make

   However, I would not suggest doing this. The library authors went out of their way to make this build for 32 bits on a 64 bit system, and it might not work correctly if you change this. (It does compile, though.)

Below is one way to debug and fix this issue. Since most linux installations differ in one way or another, YMMV.

1. Find which package installed libc-header-start.h.

$ dpkg -S libc-header-start.h
libc6-dev:amd64: /usr/include/x86_64-linux-gnu/bits/libc-header-start.h

On a working system, /usr/include/bits is a symlink to /usr/include/x86_64-linux-gnu/bits. Running dpkg search gives us:

$ dpkg -S /usr/include/bits
libc6-dev-i386: /usr/include/bits

Installing libc6-dev-i386 creates the symlink and the error is addressed.

However, subsequently I ran into a linker error with the linker not being able to find libgcc (-lgcc). Apparently Linux default linker needs libgcc in most cases. Further debugging the issue with linker verbosity enabled lead me to missing lib32gcc-10-dev package.

In short, unless a very controlled build environment is desired, just install gcc-multilib package when using -m32 (needed for gcc or clang). For C++, g++-multilib is also required.