diff -ruN mpfr-4.2.1/config.sub mpfr-4.2.1-banan_os/config.sub
--- mpfr-4.2.1/config.sub	2023-08-22 10:47:14.000000000 +0300
+++ mpfr-4.2.1-banan_os/config.sub	2024-08-07 22:48:27.798804026 +0300
@@ -1754,7 +1754,7 @@
 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
 	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
 	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
-	     | fiwix* )
+	     | fiwix* | banan_os* )
 		;;
 	# This one is extra strict with allowed versions
 	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)
