--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2012-03-07  Bruno Haible  <bruno@clisp.org>
+
+	expm1l: Don't override undeclared system function on IRIX 6.5.
+	* lib/math.in.h (expm1l): Test HAVE_DECL_EXPM1L, not HAVE_EXPM1L.
+	* m4/expm1l.m4 (gl_FUNC_EXPM1L): Don't assume expm1l() is declared when
+	it exists. Set HAVE_DECL_EXPM1L.
+	* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize HAVE_DECL_EXPM1L, not
+	HAVE_EXPM1L.
+	* modules/math (Makefile.am): Substitute HAVE_DECL_EXPM1L, not
+	HAVE_EXPM1L.
+	* doc/posix-functions/expm1l.texi: Mention missing declaration problem.
+
 2012-03-07  Bruno Haible  <bruno@clisp.org>
 
 	remainderl: Don't override undeclared system function on IRIX 6.5.

--- a/doc/posix-functions/expm1l.texi
+++ b/doc/posix-functions/expm1l.texi
@@ -10,7 +10,10 @@
 @itemize
 @item
 This function is missing on some platforms:
-FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, Cygwin, mingw, MSVC 9, Interix 3.5, BeOS.
+FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, older IRIX 6.5, Solaris 9, Cygwin, mingw, MSVC 9, Interix 3.5, BeOS.
+@item
+This function is not declared on some platforms:
+IRIX 6.5.
 @end itemize
 
 Portability problems not fixed by Gnulib:

--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -579,7 +579,7 @@
 #endif
 
 #if @GNULIB_EXPM1L@
-# if !@HAVE_EXPM1L@
+# if !@HAVE_DECL_EXPM1L@
 _GL_FUNCDECL_SYS (expm1l, long double, (long double x));
 # endif
 _GL_CXXALIAS_SYS (expm1l, long double, (long double x));

--- a/m4/expm1l.m4
+++ b/m4/expm1l.m4
@@ -1,4 +1,4 @@
-# expm1l.m4 serial 1
+# expm1l.m4 serial 2
 dnl Copyright (C) 2010-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -22,6 +22,11 @@
              # define __NO_MATH_INLINES 1 /* for glibc */
              #endif
              #include <math.h>
+             extern
+             #ifdef __cplusplus
+             "C"
+             #endif
+             long double expm1l (long double);
              long double (*funcptr) (long double) = expm1l;
              long double x;]],
            [[return funcptr (x) > 0.5
@@ -41,6 +46,11 @@
                # define __NO_MATH_INLINES 1 /* for glibc */
                #endif
                #include <math.h>
+               extern
+               #ifdef __cplusplus
+               "C"
+               #endif
+               long double expm1l (long double);
                long double (*funcptr) (long double) = expm1l;
                long double x;]],
              [[return funcptr (x) > 0.5
@@ -53,9 +63,15 @@
       EXPM1L_LIBM=-lm
     fi
   fi
-  if test $gl_cv_func_expm1l_no_libm = no \
-     && test $gl_cv_func_expm1l_in_libm = no; then
+  if test $gl_cv_func_expm1l_no_libm = yes \
+     || test $gl_cv_func_expm1l_in_libm = yes; then
+    HAVE_EXPM1L=1
+    dnl Also check whether it's declared.
+    dnl IRIX 6.5 has expm1l() in libm but doesn't declare it in <math.h>.
+    AC_CHECK_DECL([expm1l], , [HAVE_DECL_EXPM1L=0], [[#include <math.h>]])
+  else
     HAVE_EXPM1L=0
+    HAVE_DECL_EXPM1L=0
     dnl Find libraries needed to link lib/expm1l.c.
     if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
       AC_REQUIRE([gl_FUNC_EXPM1])

--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 87
+# math_h.m4 serial 88
 dnl Copyright (C) 2007-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -159,7 +159,6 @@
   HAVE_EXPL=1;                 AC_SUBST([HAVE_EXPL])
   HAVE_EXPM1=1;                AC_SUBST([HAVE_EXPM1])
   HAVE_EXPM1F=1;               AC_SUBST([HAVE_EXPM1F])
-  HAVE_EXPM1L=1;               AC_SUBST([HAVE_EXPM1L])
   HAVE_FABSF=1;                AC_SUBST([HAVE_FABSF])
   HAVE_FABSL=1;                AC_SUBST([HAVE_FABSL])
   HAVE_FMA=1;                  AC_SUBST([HAVE_FMA])
@@ -203,6 +202,7 @@
   HAVE_DECL_COPYSIGNF=1;       AC_SUBST([HAVE_DECL_COPYSIGNF])
   HAVE_DECL_COSL=1;            AC_SUBST([HAVE_DECL_COSL])
   HAVE_DECL_EXPL=1;            AC_SUBST([HAVE_DECL_EXPL])
+  HAVE_DECL_EXPM1L=1;          AC_SUBST([HAVE_DECL_EXPM1L])
   HAVE_DECL_FLOORF=1;          AC_SUBST([HAVE_DECL_FLOORF])
   HAVE_DECL_FLOORL=1;          AC_SUBST([HAVE_DECL_FLOORL])
   HAVE_DECL_FREXPL=1;          AC_SUBST([HAVE_DECL_FREXPL])

--- a/modules/math
+++ b/modules/math
@@ -127,7 +127,6 @@
 	      -e 's|@''HAVE_EXPL''@|$(HAVE_EXPL)|g' \
 	      -e 's|@''HAVE_EXPM1''@|$(HAVE_EXPM1)|g' \
 	      -e 's|@''HAVE_EXPM1F''@|$(HAVE_EXPM1F)|g' \
-	      -e 's|@''HAVE_EXPM1L''@|$(HAVE_EXPM1L)|g' \
 	      -e 's|@''HAVE_FABSF''@|$(HAVE_FABSF)|g' \
 	      -e 's|@''HAVE_FABSL''@|$(HAVE_FABSL)|g' \
 	      -e 's|@''HAVE_FMA''@|$(HAVE_FMA)|g' \
@@ -171,6 +170,7 @@
 	      -e 's|@''HAVE_DECL_COPYSIGNF''@|$(HAVE_DECL_COPYSIGNF)|g' \
 	      -e 's|@''HAVE_DECL_COSL''@|$(HAVE_DECL_COSL)|g' \
 	      -e 's|@''HAVE_DECL_EXPL''@|$(HAVE_DECL_EXPL)|g' \
+	      -e 's|@''HAVE_DECL_EXPM1L''@|$(HAVE_DECL_EXPM1L)|g' \
 	      -e 's|@''HAVE_DECL_FLOORF''@|$(HAVE_DECL_FLOORF)|g' \
 	      -e 's|@''HAVE_DECL_FLOORL''@|$(HAVE_DECL_FLOORL)|g' \
 	      -e 's|@''HAVE_DECL_FREXPL''@|$(HAVE_DECL_FREXPL)|g' \