merge revision(s) 67f4729: [Backport #18556]

	[Bug#18556] Fallback `MAP_ ANONYMOUS`

	Define `MAP_ANONYMOUS` to `MAP_ANON` if undefined on old systems.
	---
	 gc.c | 4 ++++
	 1 file changed, 4 insertions(+)

1 files changed, 4 insertions, 0 deletions

diff --git a/gc.c b/gc.c
index d77dc2cda4..ef9327df1f 100644
--- a/gc.c
+++ b/gc.c
@@ -133,6 +133,10 @@
 #define rb_jmp_buf rb_jmpbuf_t
 #undef rb_data_object_wrap
 
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
 static inline struct rbimpl_size_mul_overflow_tag
 size_add_overflow(size_t x, size_t y)
 {