Define _POSIX_C_SOURCE globally

Stop trying to maintain a per-file _POSIX_C_SOURCE. Instead,
require POSIX.1-2008 globally. A lot of core source files depend
on that already.

Some care must be taken on a few select files where we need a bit
more than POSIX. Some files need XSI extensions (_XOPEN_SOURCE) and
some files need BSD extensions (_DEFAULT_SOURCE). In both cases,
these feature test macros imply _POSIX_C_SOURCE. Make sure to not
define both these macros and _POSIX_C_SOURCE explicitly to avoid
POSIX requirement conflicts (e.g. _POSIX_C_SOURCE says POSIX.1-2001
but _XOPEN_SOURCE says POSIX.1-2008).

Additionally, there is one special case in render/vulkan/vulkan.c.
That file needs major()/minor(), and these are system-specific.
On FreeBSD, _POSIX_C_SOURCE hides system-specific symbols so we need
to make sure it's not defined for this file. On Linux, we can
explicitly include <sys/sysmacros.h> and ensure that apart from
symbols defined there the file only uses POSIX toys.

4 files changed, 0 insertions, 4 deletions

diff --git a/util/log.c b/util/log.c
index 9996ab8a..a329b43b 100644
--- a/util/log.c
+++ b/util/log.c
@@ -1,4 +1,3 @@
-#define _POSIX_C_SOURCE 200809L
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
diff --git a/util/shm.c b/util/shm.c
index 6fddebbb..5eb87bb8 100644
--- a/util/shm.c
+++ b/util/shm.c
@@ -1,4 +1,3 @@
-#define _POSIX_C_SOURCE 200112L
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
diff --git a/util/time.c b/util/time.c
index 78faac56..bc4a1063 100644
--- a/util/time.c
+++ b/util/time.c
@@ -1,4 +1,3 @@
-#define _POSIX_C_SOURCE 200809L
 #include <stdint.h>
 #include <time.h>
 
diff --git a/util/token.c b/util/token.c
index 09702e55..2d58d169 100644
--- a/util/token.c
+++ b/util/token.c
@@ -1,4 +1,3 @@
-#define _POSIX_C_SOURCE 200809L
 #include "util/token.h"
 #include "wlr/util/log.h"