--- gcc/config/mips/xm-sysv4.h	2018/04/24 18:15:55	1.1
+++ gcc/config/mips/xm-sysv4.h	2018/04/24 18:22:10	1.1.1.2
@@ -3,3 +3,9 @@
 /* SVR4 provides no sys_siglist,
    but does offer the same data under another name.  */
 #define sys_siglist _sys_siglist
+
+/* There is a declaration in /usr/include/signal.h that conflicts with the
+   declarations in collect2.c and mips-tfile.c, so disable gcc's declarations.
+   This is at least true for CDC's EP/IX 2.1.1.  It is suspected to be true
+   for RISC/OS 5.x also.  */
+#define DONT_DECLARE_SYS_SIGLIST