Note that the experimental package is failing with a different error:
gcc -I/«BUILDDIR»/clisp-2.49+hg.2015.05.31/src -I/«BUILDDIR»/clisp-2.49+hg.2015.05.31/debian/build/gllib -I/«BUILDDIR»/clisp-2.49+hg.2015.05.31/src/gllib -falign-functions=4 -W -Wswitch -Wcomment -Wpointer-arith -Wreturn-type -Wmissing-declarations -Wimplicit -O2 -DENABLE_UNICODE -DDYNAMIC_FFI -DDYNAMIC_MODULES -c lisparit.c In file included from /«BUILDDIR»/clisp-2.49+hg.2015.05.31/src/lisparit.d:28:0: /«BUILDDIR»/clisp-2.49+hg.2015.05.31/src/arilev1.d:270:26: fatal error: ariarm.c: No such file or directory compilation terminated. Makefile:1299: recipe for target 'lisparit.o' failed make[1]: *** [lisparit.o] Error 1