[PATCH] build: fix large diversions on mingw

[Eric Blake]

Gnulib's clean-temp module defaults to using _O_TEMPORARY on mingw,
which has the effect of deleting a file the first time it is closed.
This resulted in a testsuite failure in 146.diversions, with m4
complaining that it could not create a temporary file for holding a
diversion.  In reality, m4 was trying to rename the file, but
because mingw does not allow renaming an open file, we have to close
it first - but closing it first deleted the file.

For now, we will just work around the gnulib issue by disabling the
use of _O_TEMPORARY.

This was probably introduced in commit da5f6db (1.4.13), although
my testing environment was painfully slow to confirm this, so I
did not call out a 'regression since xyz' in the NEWS entry.

* gl/lib/clean-temp.c.diff: New file.

Signed-off-by: Eric Blake <address@hidden>
---

This patch fixes 'make && make -C checks test' on mingw, but there
is still a test failure in 'make check' in the gnulib directory
that will require yet another gnulib update in the near future.

 ChangeLog                |  6 ++++++
 NEWS                     |  3 +++
 gl/lib/clean-temp.c.diff | 14 ++++++++++++++
 3 files changed, 23 insertions(+)
 create mode 100644 gl/lib/clean-temp.c.diff

diff --git a/ChangeLog b/ChangeLog
index b5bb9e2..3e08dba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2013-03-11  Eric Blake  <address@hidden>
+
+       build: fix large diversions on mingw
+       * gl/lib/clean-temp.c.diff: New file.
+       * NEWS: Mention the fix.
+
 2013-03-08  Gary V. Vaughan  <address@hidden>

        bootstrap: remove reintroduced CVS cruft.
diff --git a/NEWS b/NEWS
index 25c12ea..2240772 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,9 @@ GNU M4 NEWS - User visible changes.

 ** Fix compilation with newer glibc headers.

+** Fix a failure with diverting large amounts of text on mingw (does
+   not affect platforms that can rename an open file).
+
 ** A number of portability improvements inherited from gnulib.


diff --git a/gl/lib/clean-temp.c.diff b/gl/lib/clean-temp.c.diff
new file mode 100644
index 0000000..2eafde6
--- /dev/null
+++ b/gl/lib/clean-temp.c.diff
@@ -0,0 +1,14 @@
+diff --git i/lib/clean-temp.c w/lib/clean-temp.c
+index 40ec02f..1053312 100644
+--- i/lib/clean-temp.c
++++ w/lib/clean-temp.c
+@@ -582,6 +582,9 @@ static bool
+ supports_delete_on_close ()
+ {
+   static int known; /* 1 = yes, -1 = no, 0 = unknown */
++  /* M4 wants to close and later reopen a temporary file, so
++     delete-on-close must not be used.  */
++  known = -1;
+   if (!known)
+     {
+       OSVERSIONINFO v;
-- 
1.8.1.4