Makefile-libbz2_so already contain BIGFILES=-D_FILE_OFFSET_BITS=64 CFLAGS=-fpic -fPIC -Wall -Winline -O2 -g $(BIGFILES) So bzip2-1.0.3-shared-largefile-support.patch is no more needed (and patch should fail to install). I don't know enought portage to understand why patch installation did not fail to install. ebuild log show a success * Applying bzip2-1.0.3-shared-largefile-support.patch ... [ ok ]
it's needed due to an earlier patch. ive simply merged the patches in question.