[glib/halfline-no-spawn] Revert "wip! gspawn: Disable posix_spawn on osx"

[Ray Strode <halfline src gnome org>]

commit bd47fb97e3f99b6fe9b15d375443acd71c779abd
Author: Ray Strode <rstrode redhat com>
Date:   Tue Oct 18 15:44:49 2022 -0400

    Revert "wip! gspawn: Disable posix_spawn on osx"
    
    This reverts commit 4ac8bc6a62fafb2751a92161c81a63ebd696969f.

 glib/gspawn.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/glib/gspawn.c b/glib/gspawn.c
index 87af46cc56..4e029eedf5 100644
--- a/glib/gspawn.c
+++ b/glib/gspawn.c
@@ -83,11 +83,9 @@
 #define POSIX_SPAWN_AVAILABLE
 #endif
 
-#undef POSIX_SPAWN_AVAILABLE
-
 #else /* !__GLIBC__ */
 /* Assume that all non-glibc posix_spawn implementations are fine. */
-#undef POSIX_SPAWN_AVAILABLE
+#define POSIX_SPAWN_AVAILABLE
 #endif /* __GLIBC__ */
 #endif /* HAVE_POSIX_SPAWN */