libvirt/build-aux
Daniel P. Berrangé fdd941eeb2 build: workaround behaviour regression in gnu make 4.3
We need the "$(space)" variable to contain a single whitespace
character. We do this by assigning and then appending an empty
string to the variable. Variable appends get separated by a
single whitespace historically, but GNU make 4.3 introduced a
behaviour regression.

  https://lists.gnu.org/archive/html/bug-make/2020-01/msg00057.html

[quote]
* WARNING: Backward-incompatibility!
  Previously appending using '+=' to an empty variable would
  result in a value starting with a space.  Now the initial
  space is only added if the variable already contains some
  value.  Similarly, appending an empty string does not
  add a trailing space.
[/quote]

This patch tries a new trick to get a single whitespace by
getting make to expand two non-existant variables separated
by a space.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-03-16 12:07:21 +00:00
..
check-spacing.pl Remove all Author(s): lines from source file headers 2018-12-13 16:08:38 +00:00
syntax-check.mk build: workaround behaviour regression in gnu make 4.3 2020-03-16 12:07:21 +00:00
useless-if-before-free build: import gnulib's syntax-check make rules 2019-10-09 13:36:29 +01:00
vc-list-files build: import gnulib's syntax-check make rules 2019-10-09 13:36:29 +01:00