diff --git a/configure.in b/configure.in
index a5e34d7cde5..bc82b0606b0 100644
--- a/configure.in
+++ b/configure.in
@@ -223,7 +223,7 @@ AC_CHECK_LIB(sun, getpwnam)	# NIS (== YP) interface for IRIX 4
 # broken.  I see no elegant solution (probably CHECK_LIB should be
 # fixed to only add the library if the given entry point is not
 # satisfied without it).
-if test "`uname -s`" != IRIX
+if test "$ac_sys_system" != IRIX
 then
 AC_CHECK_LIB(nsl, t_open, [LIBS="-lnsl $LIBS"]) # SVR4
 AC_CHECK_LIB(inet, gethostbyname, [LIBS="-linet $LIBS"], [], -lnsl) # Sequent
@@ -321,7 +321,7 @@ AC_CHECK_FUNCS(chown clock dlopen flock ftime ftruncate \
  select setgid setuid setsid setpgid setpgrp setvbuf \
  sigaction siginterrupt sigrelse strftime symlink \
  tcgetpgrp tcsetpgrp times truncate uname waitpid)
-AC_REPLACE_FUNCS(dup2 getcwd strerror memmove)
+AC_REPLACE_FUNCS(dup2 getcwd strdup strerror memmove)
 AC_CHECK_FUNC(getpgrp, AC_TRY_COMPILE([#include <unistd.h>], [getpgrp(0);], AC_DEFINE(GETPGRP_HAVE_ARG)))
 AC_CHECK_FUNC(setpgrp, AC_TRY_COMPILE([#include <unistd.h>], [setpgrp(0,0);], AC_DEFINE(SETPGRP_HAVE_ARG)))
 AC_CHECK_FUNC(gettimeofday, AC_TRY_COMPILE([#include <sys/time.h>], [gettimeofday((struct timeval*)0,(struct timezone*)0);], ,AC_DEFINE(GETTIMEOFDAY_NO_TZ)))
@@ -445,6 +445,7 @@ fi])
 LIBS_SAVE=$LIBS
 LIBS="$LIBS $LIBM"
 AC_CHECK_FUNCS(hypot)
+AC_REPLACE_FUNCS(hypot)
 LIBS=$LIBS_SAVE
 
 # check for getopt