Index: llvm-toolchain-15-15.0.0~+rc3/compiler-rt/lib/builtins/clear_cache.c
===================================================================
--- llvm-toolchain-15-15.0.0~+rc3.orig/compiler-rt/lib/builtins/clear_cache.c
+++ llvm-toolchain-15-15.0.0~+rc3/compiler-rt/lib/builtins/clear_cache.c
@@ -6,6 +6,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if defined(__linux__) && defined(__mips__)
+// Otherwise, the build fails as it cannot find syscall
+#define _GNU_SOURCE
+#endif
+
 #include "int_lib.h"
 #if defined(__linux__)
 #include <assert.h>