Replace AC_TRY_COMPILE obsoleted in autoconf 2.70.

Replace with the equivalent AC_COMPILE_IFELSE.

m4/openssh.m4

@@ -171,14 +171,15 @@ AC_DEFUN([TYPE_SOCKLEN_T],
 	 curl_cv_socklen_t_equiv=
 	 for arg2 in "struct sockaddr" void; do
 	    for t in int size_t unsigned long "unsigned long"; do
-	       AC_TRY_COMPILE([
-		  #include <sys/types.h>
-		  #include <sys/socket.h>
-
-		  int getpeername (int, $arg2 *, $t *);
-	       ],[
-		  $t len;
-		  getpeername(0,0,&len);
+	       AC_COMPILE_IFELSE([
+		  AC_LANG_PROGRAM([[
+		    #include <sys/types.h>
+		    #include <sys/socket.h>
+		    int getpeername (int, $arg2 *, $t *);
+		  ]], [[
+		    $t len;
+		    getpeername(0,0,&len);
+		  ]])
 	       ],[
 		  curl_cv_socklen_t_equiv="$t"
 		  break