### C.4 Specific advice for GNU/Linux systems

If you are installing the GNU C Library on GNU/Linux systems, you need to have the header files from a 2.6.19.1 or newer kernel around for reference. These headers must be installed using ‘`make headers_install`’; the headers present in the kernel source directory are not suitable for direct use by the GNU C Library. You do not need to use that kernel, just have its headers installed where the GNU C Library can access them, referred to here as install-directory. The easiest way to do this is to unpack it in a directory such as `/usr/src/linux-version`. In that directory, run ‘`make headers_install INSTALL_HDR_PATH=install-directory`’. Finally, configure the GNU C Library with the option ‘`--with-headers=install-directory/include`’. Use the most recent kernel you can get your hands on. (If you are cross-compiling the GNU C Library, you need to specify ‘`ARCH=architecture`’ in the ‘`make headers_install`’ command, where architecture is the architecture name used by the Linux kernel, such as ‘`x86`’ or ‘`powerpc`’.)

After installing the GNU C Library, you may need to remove or rename directories such as `/usr/include/linux` and `/usr/include/asm`, and replace them with copies of directories such as `linux` and `asm` from `install-directory/include`. All directories present in `install-directory/include` should be copied, except that the GNU C Library provides its own version of `/usr/include/scsi`; the files provided by the kernel should be copied without replacing those provided by the GNU C Library. The `linux`, `asm` and `asm-generic` directories are required to compile programs using the GNU C Library; the other directories describe interfaces to the kernel but are not required if not compiling programs using those interfaces. You do not need to copy kernel headers if you did not specify an alternate kernel header source using ‘`--with-headers`’.

The Filesystem Hierarchy Standard for GNU/Linux systems expects some components of the GNU C Library installation to be in `/lib` and some in `/usr/lib`. This is handled automatically if you configure the GNU C Library with ‘`--prefix=/usr`’. If you set some other prefix or allow it to default to `/usr/local`, then all the components are installed there.