Prevent race condition in `-dfont-ps-resdir` (issue 561810045 by address@hidden)

[lemzwerg]

LGTM, with minor nits.


https://codereview.appspot.com/561810045/diff/551840043/scm/backend-library.scm
File scm/backend-library.scm (right):

https://codereview.appspot.com/561810045/diff/551840043/scm/backend-library.scm#newcode143
scm/backend-library.scm:143: ;; When the directory already exists, it
raises system-error.
s/When/If/

https://codereview.appspot.com/561810045/diff/551840043/scm/backend-library.scm#newcode161
scm/backend-library.scm:161: ;; When the file already exists, it raises
system-error.
s/When/If/

https://codereview.appspot.com/561810045/diff/551840043/scm/backend-library.scm#newcode188
scm/backend-library.scm:188: ;; When the file already exists, it raises
system-error.
s/When/If/

https://codereview.appspot.com/561810045/diff/551840043/scm/framework-ps.scm
File scm/framework-ps.scm (right):

https://codereview.appspot.com/561810045/diff/551840043/scm/framework-ps.scm#newcode284
scm/framework-ps.scm:284: from file `~a' index ~a...")
Maybe

  for subfont ~a of file ~a")

?

https://codereview.appspot.com/561810045/diff/551840043/scm/framework-ps.scm#newcode544
scm/framework-ps.scm:544: (_ "Font file `~a' already exists, skipping.")
s/\./.../ to be in sync with other, similar error messages.

Alternatively, you might do s/\.\.\././ in the other error messages :-)

https://codereview.appspot.com/561810045/