I was tracking down a build error for LUFA where it complained about invalid suffix 'x' on the symbol BOOT_START_ADDR in BootloaderCDC.c. It turns out, "bc" was not installed on my system, which generated an empty boot start address in the makefile.
However, while tracking this down, each top-level "make" in the LUFA-120730 directory appears to re-build everything. This takes a while! Why is this? Make is supposed to only re-build targets that need changing, and proper dependencies are easy to generate with "gcc -MMD"?