diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 783e5ec7b13..8c950159904 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+Mon Sep  1 08:29:46 1997  Jeffrey A Law  (law@cygnus.com)
+
+	* collect2.c: Change DONT_DECLARE_SYS_SIGLIST to SYS_SIGLIST_DECLARED.
+	* mips-tfile.c: Likewise.
+	* gcc.texi: DONT_DECLARE_SYS_SIGLIST: Remove docs.
+	* xm-linux.h (DONT_DECLARE_SYS_SIGLIST): Delete definition.
+	* xm-freebsd.h, xm-bsd386.h, xm-sysv4.h, xm-sol2.h: Likewise.
+	* configure.in: Check for sys_siglist declaration.
+	* configure, config.in: Rebuilt.
+
 Mon Sep  1 08:04:07 1997  Joel Sherrill (joel@OARcorp.com)
 
 	* i386/go32-rtems.h, i386/rtems.h, i960/rtems.h, 
diff --git a/gcc/collect2.c b/gcc/collect2.c
index 64d98d78db7..13cb59367bb 100644
--- a/gcc/collect2.c
+++ b/gcc/collect2.c
@@ -213,7 +213,7 @@ enum pass {
 };
 
 #ifndef NO_SYS_SIGLIST
-#ifndef DONT_DECLARE_SYS_SIGLIST
+#ifndef SYS_SIGLIST_DECLARED
 extern char *sys_siglist[];
 #endif
 #endif
diff --git a/gcc/config.in b/gcc/config.in
index 504e1bb2bc6..f14c397b9dc 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -16,6 +16,9 @@
 /* Whether free must be declared even if <stdlib.h> is included.  */
 #undef NEED_DECLARATION_FREE
 
+/* Define if `sys_siglist' is declared by <signal.h>.  */
+#undef SYS_SIGLIST_DECLARED
+
 /* Define if you have the <stddef.h> header file.  */
 #undef HAVE_STDDEF_H
 
diff --git a/gcc/config/alpha/xm-linux.h b/gcc/config/alpha/xm-linux.h
index 9426c4ee5a7..1333d2160c3 100644
--- a/gcc/config/alpha/xm-linux.h
+++ b/gcc/config/alpha/xm-linux.h
@@ -1,3 +1,2 @@
 #define HAVE_STRERROR
-#define DONT_DECLARE_SYS_SIGLIST
 #define USE_BFD
diff --git a/gcc/config/i386/xm-bsd386.h b/gcc/config/i386/xm-bsd386.h
index 7a823b96032..abcce3f01cb 100644
--- a/gcc/config/i386/xm-bsd386.h
+++ b/gcc/config/i386/xm-bsd386.h
@@ -3,9 +3,3 @@
 #include "i386/xm-i386.h"
 
 #define HAVE_STRERROR
-
-/* We have _sys_siglist, but the declaration in <signal.h> conflicts with
-   the declarations in collect2.c so disable the declarations
-   in those files.  */
-
-#define DONT_DECLARE_SYS_SIGLIST
diff --git a/gcc/config/i386/xm-sysv4.h b/gcc/config/i386/xm-sysv4.h
index cf111a09ced..49d52b4e7f3 100644
--- a/gcc/config/i386/xm-sysv4.h
+++ b/gcc/config/i386/xm-sysv4.h
@@ -14,9 +14,3 @@
 /* Univel, at least, has a small ARG_MAX.  Defining this is harmless
    except for causing extra stat calls in the driver program.  */
 #define SMALL_ARG_MAX
-
-/* We have _sys_siglist, but the declaration in <signal.h> conflicts with
-   the declarations in collect2.c and mips-tfile.c, so disable the declarations
-   in those files.  */
-
-#define DONT_DECLARE_SYS_SIGLIST
diff --git a/gcc/config/mips/xm-sysv4.h b/gcc/config/mips/xm-sysv4.h
index 490a7722995..bed4405e1b7 100644
--- a/gcc/config/mips/xm-sysv4.h
+++ b/gcc/config/mips/xm-sysv4.h
@@ -3,9 +3,3 @@
 /* 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
diff --git a/gcc/config/rs6000/xm-sysv4.h b/gcc/config/rs6000/xm-sysv4.h
index 5283dfcf98a..3a13a579461 100644
--- a/gcc/config/rs6000/xm-sysv4.h
+++ b/gcc/config/rs6000/xm-sysv4.h
@@ -56,9 +56,6 @@ extern char *alloca ();
 #define ONLY_INT_FIELDS
 #endif
 
-/* Solaris has a different declaration of sys_siglist than collect uses.  */
-#define DONT_DECLARE_SYS_SIGLIST
-
 /* We have STRERROR */
 #define HAVE_STRERROR
 
diff --git a/gcc/config/sparc/xm-sol2.h b/gcc/config/sparc/xm-sol2.h
index 234ed999d05..a799f12b946 100644
--- a/gcc/config/sparc/xm-sol2.h
+++ b/gcc/config/sparc/xm-sol2.h
@@ -4,9 +4,3 @@
 #ifndef __GNUC__
 #include <alloca.h>
 #endif
-
-/* We have _sys_siglist, but the declaration in <signal.h> conflicts with
-   the declarations in collect2.c and mips-tfile.c, so disable the declarations
-   in those files.  */
-
-#define DONT_DECLARE_SYS_SIGLIST
diff --git a/gcc/config/xm-freebsd.h b/gcc/config/xm-freebsd.h
index f73c9aa60fa..ab3aa114382 100644
--- a/gcc/config/xm-freebsd.h
+++ b/gcc/config/xm-freebsd.h
@@ -25,9 +25,3 @@ Boston, MA 02111-1307, USA.  */
    
 /* FreeBSD has strerror.  */
 #define HAVE_STRERROR
-
-/* We have _sys_siglist, but the declaration in <signal.h> conflicts with
-   the declarations in collect2.c and mips-tfile.c, so disable the declarations
-   in those files.  */
-
-#define DONT_DECLARE_SYS_SIGLIST
diff --git a/gcc/config/xm-linux.h b/gcc/config/xm-linux.h
index 88b558cc5bf..4ccf001173b 100644
--- a/gcc/config/xm-linux.h
+++ b/gcc/config/xm-linux.h
@@ -31,9 +31,6 @@ Boston, MA 02111-1307, USA.  */
 #undef  POSIX
 #define POSIX
 
-#undef  DONT_DECLARE_SYS_SIGLIST
-#define DONT_DECLARE_SYS_SIGLIST
-
 /* We do have one, but I'd like to use the one come with gcc since
    we have been doing that for a long time with USG defined.  H.J. */
 #define NO_STAB_H
diff --git a/gcc/configure b/gcc/configure
index 44445181232..b91c782f123 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 # Guess values for system-dependent variables and create Makefiles.
-# Generated automatically using autoconf version 2.12.1 
+# Generated automatically using autoconf version 2.12 
 # Copyright (C) 1992, 93, 94, 95, 96 Free Software Foundation, Inc.
 #
 # This configure script is free software; the Free Software Foundation
@@ -350,7 +350,7 @@ EOF
     verbose=yes ;;
 
   -version | --version | --versio | --versi | --vers)
-    echo "configure generated by autoconf version 2.12.1"
+    echo "configure generated by autoconf version 2.12"
     exit 0 ;;
 
   -with-* | --with-*)
@@ -704,7 +704,7 @@ esac
 
 
 # Make sure we can run config.sub.
-if ${CONFIG_SHELL-/bin/sh} $ac_config_sub sun4 >/dev/null 2>&1; then :
+if $ac_config_sub sun4 >/dev/null 2>&1; then :
 else { echo "configure: error: can not run $ac_config_sub" 1>&2; exit 1; }
 fi
 
@@ -716,14 +716,14 @@ case "$host_alias" in
 NONE)
   case $nonopt in
   NONE)
-    if host_alias=`${CONFIG_SHELL-/bin/sh} $ac_config_guess`; then :
+    if host_alias=`$ac_config_guess`; then :
     else { echo "configure: error: can not guess host type; you must specify one" 1>&2; exit 1; }
     fi ;;
   *) host_alias=$nonopt ;;
   esac ;;
 esac
 
-host=`${CONFIG_SHELL-/bin/sh} $ac_config_sub $host_alias`
+host=`$ac_config_sub $host_alias`
 host_cpu=`echo $host | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\1/'`
 host_vendor=`echo $host | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\2/'`
 host_os=`echo $host | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\3/'`
@@ -741,7 +741,7 @@ NONE)
   esac ;;
 esac
 
-target=`${CONFIG_SHELL-/bin/sh} $ac_config_sub $target_alias`
+target=`$ac_config_sub $target_alias`
 target_cpu=`echo $target | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\1/'`
 target_vendor=`echo $target | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\2/'`
 target_os=`echo $target | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\3/'`
@@ -759,7 +759,7 @@ NONE)
   esac ;;
 esac
 
-build=`${CONFIG_SHELL-/bin/sh} $ac_config_sub $build_alias`
+build=`$ac_config_sub $build_alias`
 build_cpu=`echo $build | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\1/'`
 build_vendor=`echo $build | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\2/'`
 build_os=`echo $build | sed 's/^\([^-]*\)-\([^-]*\)-\(.*\)$/\3/'`
@@ -1521,6 +1521,45 @@ EOF
 fi
 
 
+echo $ac_n "checking for sys_siglist declaration in signal.h or unistd.h""... $ac_c" 1>&6
+echo "configure:1526: checking for sys_siglist declaration in signal.h or unistd.h" >&5
+if eval "test \"`echo '$''{'ac_cv_decl_sys_siglist'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+  cat > conftest.$ac_ext <<EOF
+#line 1531 "configure"
+#include "confdefs.h"
+#include <sys/types.h>
+#include <signal.h>
+/* NetBSD declares sys_siglist in unistd.h.  */
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+int main() {
+char *msg = *(sys_siglist + 1);
+; return 0; }
+EOF
+if { (eval echo configure:1543: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+  rm -rf conftest*
+  ac_cv_decl_sys_siglist=yes
+else
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  ac_cv_decl_sys_siglist=no
+fi
+rm -f conftest*
+fi
+
+echo "$ac_t""$ac_cv_decl_sys_siglist" 1>&6
+if test $ac_cv_decl_sys_siglist = yes; then
+  cat >> confdefs.h <<\EOF
+#define SYS_SIGLIST_DECLARED 1
+EOF
+
+fi
+
+
 # File extensions
 manext='.1'
 objext='.o'
@@ -4481,7 +4520,6 @@ ${CONFIG_SHELL-/bin/sh} $srcdir/configure.frag $srcdir "$subdirs" "$dep_host_xma
 
 
 
-
 
 
 # Echo that links are built
@@ -4605,7 +4643,7 @@ do
     echo "running \${CONFIG_SHELL-/bin/sh} $0 $ac_configure_args --no-create --no-recursion"
     exec \${CONFIG_SHELL-/bin/sh} $0 $ac_configure_args --no-create --no-recursion ;;
   -version | --version | --versio | --versi | --vers | --ver | --ve | --v)
-    echo "$CONFIG_STATUS generated by autoconf version 2.12.1"
+    echo "$CONFIG_STATUS generated by autoconf version 2.12"
     exit 0 ;;
   -help | --help | --hel | --he | --h)
     echo "\$ac_cs_usage"; exit 0 ;;
diff --git a/gcc/configure.in b/gcc/configure.in
index 7027f31458a..cb2d6f1bffc 100644
--- a/gcc/configure.in
+++ b/gcc/configure.in
@@ -140,6 +140,8 @@ GCC_NEED_DECLARATION(realloc)
 GCC_NEED_DECLARATION(calloc)
 GCC_NEED_DECLARATION(free)
 
+AC_DECL_SYS_SIGLIST
+
 # File extensions
 manext='.1'
 objext='.o'
diff --git a/gcc/gcc.texi b/gcc/gcc.texi
index 418dcbc57d0..40767c2d9e2 100644
--- a/gcc/gcc.texi
+++ b/gcc/gcc.texi
@@ -3718,11 +3718,6 @@ system.
 Define this if your system @emph{does not} provide the variable
 @code{sys_siglist}.
 
-@findex DONT_DECLARE_SYS_SIGLIST
-@item DONT_DECLARE_SYS_SIGLIST
-Define this if your system has the variable @code{sys_siglist}, and
-there is already a declaration of it in the system header files.
-
 @findex USE_PROTOTYPES
 @item USE_PROTOTYPES
 Define this to be 1 if you know that the host compiler supports
diff --git a/gcc/mips-tfile.c b/gcc/mips-tfile.c
index 4cd18d0fb46..4fb2f31ec04 100644
--- a/gcc/mips-tfile.c
+++ b/gcc/mips-tfile.c
@@ -1767,7 +1767,7 @@ extern int   optind;
 extern int   opterr;
 extern char *version_string;
 #ifndef NO_SYS_SIGLIST
-#ifndef DONT_DECLARE_SYS_SIGLIST
+#ifndef SYS_SIGLIST_DECLARED
 extern char *sys_siglist[NSIG + 1];
 #endif
 #endif