build: Look for mkostemp when configuring

We use this function, but it may be missing on older Linux platforms.

https://bugzilla.gnome.org/show_bug.cgi?id=788705

config.h.meson

@@ -376,6 +376,9 @@
 /* Define to 1 if you have the `statvfs' function. */
 #mesondefine HAVE_STATVFS
 
+/* Define to 1 if you have the `mkostemp' function. */
+#mesondefine HAVE_MKOSTEMP
+
 /* Define to 1 if you have the <stddef.h> header file. */
 #mesondefine HAVE_STDDEF_H
 

configure.ac

@@ -880,7 +880,7 @@ int main ()
 AC_MSG_RESULT($glib_ssize_type)
 
 # Check for some functions
-AC_CHECK_FUNCS(lstat strsignal vsnprintf stpcpy strcasecmp strncasecmp poll vasprintf setenv unsetenv getc_unlocked readlink symlink fdwalk)
+AC_CHECK_FUNCS(lstat strsignal vsnprintf stpcpy strcasecmp strncasecmp poll vasprintf setenv unsetenv getc_unlocked readlink symlink fdwalk mkostemp)
 AC_CHECK_FUNCS(lchmod lchown fchmod fchown utimes getresuid)
 AC_CHECK_FUNCS(getmntent_r setmntent endmntent hasmntopt getfsstat getvfsstat fallocate)
 case $host_os in aix*) ac_cv_func_splice=no ;; esac # AIX splice() is something else

meson.build

@@ -451,6 +451,14 @@ else
 endif
 message('Checking whether to use statfs or statvfs .. ' + stat_func_to_use)
 
+if host_system == 'linux'
+  if cc.has_function('mkostemp',
+                     prefix: '''#define _GNU_SOURCE
+                                #include <stdlib.h>''')
+    glib_conf.set('HAVE_MKOSTEMP', 1)
+  endif
+endif
+
 # Mac OS X Carbon support
 glib_have_carbon = cc.compiles('''#include <Carbon/Carbon.h>
                                   #include <CoreServices/CoreServices.h>''',