Xtensa supports mmap, enable it in absl/base/config.h

PiperOrigin-RevId: 688971140
Change-Id: I11283c77c3df8fc9b964bfb58a46211b8783cdb4
diff --git a/absl/base/config.h b/absl/base/config.h
index ab1e986..58077a2 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -380,7 +380,7 @@
     defined(__asmjs__) || defined(__EMSCRIPTEN__) || defined(__Fuchsia__) || \
     defined(__sun) || defined(__myriad2__) || defined(__HAIKU__) ||          \
     defined(__OpenBSD__) || defined(__NetBSD__) || defined(__QNX__) ||       \
-    defined(__VXWORKS__) || defined(__hexagon__)
+    defined(__VXWORKS__) || defined(__hexagon__) || defined(__XTENSA__)
 #define ABSL_HAVE_MMAP 1
 #endif