On 03/14/2014 12:55 PM, Jiri Denemark wrote:
On Fri, Mar 14, 2014 at 07:54:58 -0600, Eric Blake wrote:
On 03/14/2014 04:43 AM, Jiri Denemark wrote:
Ancient automake (such as from RHEL5) does not provide abs_srcdir and abs_builddir variables which are used by a recent commit of mine (e562e82).
Signed-off-by: Jiri Denemark <jdenemar@redhat.com> ---
+# old automake does not provide abs_{src,build}dir variables +abs_builddir = $(shell pwd) +abs_srcdir = $(shell cd $(srcdir) && pwd)
Hmm, just noticed another thing - with NEWER automake, we are now less efficient (calling out to $(shell) overwrites the value that is already provided for free without a subprocess by newer automake). Does it work if you use: abs_builddir ?= $(shell pwd)
Luckily we require GNU make, so this works. It would be nice, however, if src/Makefile.am and tests/Makefile.am shared the same formulas; right now, tests/Makefile.am uses the more portable (but slower):
AM_CFLAGS = ... -Dabs_builddir="\"`pwd`\"" \ -Dabs_srcdir="\"`cd '$(srcdir)'; pwd`\"" \
Which is unusable in this case, because we don't need to pass the variables to the compiler. It's make itself that needs to consume the variables:
$(abs_builddir)/cpu/cpu_map.xml: $(AM_V_GEN)ln -s $(abs_srcdir)/cpu/cpu_map.xml $@
The $(abs_srcdir) could be inlined with ``, but you are right that the use of $(abs_builddir) has to be expanded up front for make to track the right file in its dependency. So ACK to this patch if the switch to ?= instead of = works. It still might be nice to update tests/Makefile.am in a followup to use $(shell) instead of `` (since $(shell) is more efficient), but that's not for this patch. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org