diff --git a/config.h.in b/config.h.in
index f2393da..6d01d3b 100644
--- a/config.h.in
+++ b/config.h.in
@@ -396,3 +396,6 @@
 
 /* Define if you have the ieee library (-lieee).  */
 #undef HAVE_LIBIEEE
+
+/* Define if you have the m library (-lm).  */
+#undef HAVE_LIBM
diff --git a/configure.in b/configure.in
index af122df..e96402c 100644
--- a/configure.in
+++ b/configure.in
@@ -345,14 +345,14 @@
 # checks for libraries
 AC_CHECK_LIB(dl, dlopen)	# Dynamic linking for SunOS/Solaris and SYSV
 AC_CHECK_LIB(dld, shl_load)	# Dynamic linking for HP-UX
-AC_CHECK_LIB(sun, getpwnam)	# NIS (== YP) interface for IRIX 4
+AC_CHECK_LIB(m, pow)		# Std math lib -- assume needed if it exists
 # Most SVR4 platforms (e.g. Solaris) need -lsocket and -lnsl.
 # However on SGI IRIX, these exist but are broken.
-if test "$ac_sys_system" != IRIX
-then
+case "$ac_sys_system" in IRIX*) ;;
+*)
 AC_CHECK_LIB(nsl, t_open, [LIBS="-lnsl $LIBS"]) # SVR4
 AC_CHECK_LIB(socket, socket, [LIBS="-lsocket $LIBS"], [], $LIBS) # SVR4 sockets
-fi
+;; esac
 
 AC_MSG_CHECKING(for --with-libs)
 AC_ARG_WITH(libs, [--with-libs='lib1 ...'    link against additional libs], [