SRILM note: the use of MACHINE_TYPE for customized compilation

SRILM supports compilation for different architectures by the MACHINE_TYPE variable. By default, MACHINE_TYPE is defined automatically. However, for special purposes, such as 64 bit support, MACHINE_TYPE can be manually specified. For a particular machine type x (i.e. i686, i686-m64, i686-gcc4), the corresponding compiler options are defined in common/Makefile.machine.x. When running 'make MACHINE_TYPE=x', a separate folder x will be created under bin, lib, lm/obj, dstruct/obj and other folders. The fact can be taken advantage of when making a specific compilation of the code. For example, suppose that we want to compile a position independent version of srilm for sharing. We can do this by copying one machine specific makefile, such as Makefile.machine.i686, to Makefile.machine.foo. Then we can modify the compiler flag of foo, adding what we need. For this particular case, it is -fPIC. Then we compile srilm by 'make MACHINE_TYPE=foo'. The resulting objects, such as liboolm.a, will be placed at lib/foo. This is handy since it does not clash with existing libraries and binaries.