12a1ddc160
Using ccache with CCACHE_BASEDIR set to $(SRC_PATH) or a parent will rewrite all absolute paths to relative paths. This interacts poorly with QEMU's two-level build directory scheme. For example, lets say BUILD_DIR=$(SRC_PATH)/build so build/blockdev.d will contain: blockdev.o: ../blockdev.c ../include/sysemu/block-backend.h \ Now the target build under build/x86_64-softmmu or similar will depend on ../blockdev.o which in turn will get make to source ../blockdev.d to check its dependencies. Since make always considers paths relative to the current working directory rather than the makefile the path appeared in the relative path to ../blockdev.c is useless. This change simply adds the top level build directory to vpath so paths relative to the source directory, top build directory, and target build directory all work just fine. Signed-off-by: Michael Marineau <michael.marineau@coreos.com> Message-Id: <1439103775-11836-1-git-send-email-michael.marineau@coreos.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org - QEMU team