Building a testdir on Haiku, I see this compilation error:
gcc -DHAVE_CONFIG_H -DEXEEXT=\"\" -DEXEEXT=\"\" -DNO_XMALLOC -DEXEEXT=\"\" -I.
-I../../gllib -I.. -DGNULIB_STRICT_CHECKING=1
-I/boot/home/config/non-packaged/include -Wall -fvisibility=hidden -g -O2 -MT
nonblocking.o -MD -MP -MF $depbase.Tpo -c -o nonblocking.o
../../gllib/nonblocking.c &&\
mv -f $depbase.Tpo $depbase.Po
../../gllib/nonblocking.c:129:4: error: #error Please port nonblocking to your
platform
129 | # error Please port nonblocking to your platform
| ^~~~~
Makefile:12111: recipe for target 'nonblocking.o' failed
make[4]: *** [nonblocking.o] Error 1
The cause is the recursive include <fcntl.h> -> <unistd.h> -> <fcntl.h>,
that was introduced on 2025-02-16 and that has the effect that fcntl.h
examines the value of O_NONBLOCKING before this macro has gotten its
final value.
This patch fixes it.
2025-03-12 Bruno Haible <br...@clisp.org>
fcntl-h: Fix GNULIB_defined_O_NONBLOCK on Haiku (regr. 2025-02-16).
* lib/fcntl.in.h (_@GUARD_PREFIX@_ALREADY_INCLUDING_FCNTL_H): New macro.
diff --git a/lib/fcntl.in.h b/lib/fcntl.in.h
index ac61c0865a..d7f551b30f 100644
--- a/lib/fcntl.in.h
+++ b/lib/fcntl.in.h
@@ -22,8 +22,12 @@
#endif
@PRAGMA_COLUMNS@
-#if defined __need_system_fcntl_h
-/* Special invocation convention. */
+#if defined __need_system_fcntl_h || defined
_@GUARD_PREFIX@_ALREADY_INCLUDING_FCNTL_H
+/* Special invocation convention:
+ - On Haiku we have a sequence of nested includes
+ <fcntl.h> -> <unistd.h> -> <fcntl.h>
+ In this situation, GNULIB_defined_O_NONBLOCK gets defined before the
+ system's definition of O_NONBLOCK is processed. */
/* Needed before <sys/stat.h>.
May also define off_t to a 64-bit type on native Windows. */
@@ -50,6 +54,8 @@
#ifndef _@GUARD_PREFIX@_FCNTL_H
+#define _@GUARD_PREFIX@_ALREADY_INCLUDING_FCNTL_H
+
/* Needed before <sys/stat.h>.
May also define off_t to a 64-bit type on native Windows.
Also defines off64_t on macOS, NetBSD, OpenBSD, MSVC, Cygwin, Haiku. */
@@ -72,6 +78,8 @@
# include <io.h>
#endif
+#undef _@GUARD_PREFIX@_ALREADY_INCLUDING_FCNTL_H
+
#ifndef _@GUARD_PREFIX@_FCNTL_H
#define _@GUARD_PREFIX@_FCNTL_H
