[glib] Fix the "/proc/self/cmdline" test

[LRN <ruslanizhb src gnome org>]

commit 7a399e859d80d5d8ae1be9b119dc43a2f2eebe93
Author: Руслан Ижбулатов <lrn1986 gmail com>
Date:   Sun Apr 7 18:41:39 2019 +0000

    Fix the "/proc/self/cmdline" test
    
    Add a missing ifdef from gfileutils.c that is needed for O_BINARY.
    
    The other option was to remove O_BINARY, but i left it there for
    the sake of completeness, as this is what g_file_get_contents() uses.

 meson.build | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/meson.build b/meson.build
index 64392a556..b80264759 100644
--- a/meson.build
+++ b/meson.build
@@ -1910,6 +1910,9 @@ static int
 __getcmdline (void)
 {
 /* This code is a dumbed-down version of g_file_get_contents() */
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
 #define BUFSIZE 1024
   char result[BUFSIZE];
   struct stat stat_buf;