automake vs. GNU make

Other compilers are generally supported. autoconf supports anything which 
runs as $CC and supports -g, -o, and -c with the customary meanings; 
automake supports anything with the caveat that dependency analysis may be 
inaccurate without compiler support (said support being a few lines of 
shell script in the depcomp script: if you need it for your compiler, 
please submit a patch!)

libtool's support is necessarily compiler-by-compiler and 
platform-by-platform, and so cannot cover everything (its entire purpose 
being to smooth out variation in the way different compilers and platforms 
create shared objects): nonetheless, on Linux, 1.5.26 supports GCC, KCC, 
Intel C++, the Portland Group's compiler, Compaq C++, and even Sun C, 
although who'd be using that on a Linux box I have no clue. (For a 
complete list of compiler * platform combinations, look in libtool.m4.)

(libtool obviously doesn't support sdcc, since as far as I can tell sdcc 
can't generate PIC code at all :) )