For certain non-gcc compilers, alloca_h is defined (included) but there,
no alloca() is declared. Fallback to malloc if _ALLOCA_H is defined but
still, there is no alloca() in the included _ALLOCA_H.
modified Kbuild system I put into uClibc. With this, there should be no more
need to modify Rules.mak since I've moved all the interesting options into the
config system. I think I've got everything updated, but you never know, I may
have made some mistakes, so watch closely.
-Erik
