diff --git a/builtin_ulimit.c b/builtin_ulimit.c
index 16974c555..9c0653bba 100644
--- a/builtin_ulimit.c
+++ b/builtin_ulimit.c
@@ -63,13 +63,13 @@ const static struct resource_t resource_arr[] =
 		RLIMIT_FSIZE, L"Maximum size of files created by the shell", L'f', 1024
 	}
 	,
-#if HAVE_RLIMIT_MEMLOCK
+#ifdef RLIMIT_MEMLOCK
 	{
 		RLIMIT_MEMLOCK, L"Maximum size that may be locked into memory", L'l', 1024
 	}
 	,
 #endif
-#if HAVE_RLIMIT_RSS
+#ifdef RLIMIT_RSS
 	{
 		RLIMIT_RSS, L"Maximum resident set size", L'm', 1024
 	}
@@ -87,13 +87,13 @@ const static struct resource_t resource_arr[] =
 		RLIMIT_CPU, L"Maximum amount of cpu time in seconds", L't', 1
 	}
 	,
-#if HAVE_RLIMIT_NPROC
+#ifdef RLIMIT_NPROC
 	{
 		RLIMIT_NPROC, L"Maximum number of processes available to a single user", L'u', 1
 	}
 	,
 #endif
-#if HAVE_RLIMIT_AS
+#ifdef RLIMIT_AS
 	{
 		RLIMIT_AS, L"Maximum amount of virtual memory available to the shell", L'v', 1024
 	}	
diff --git a/configure.ac b/configure.ac
index 9d2f103d5..4d3c7803f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -326,53 +326,6 @@ if test "$ac_cv_func_fwprintf" = yes; then
 
 fi
 
-# Check for RLIMIT_NPROC in sys/resource.h.
-AC_MSG_CHECKING([for RLIMIT_NPROC in sys/resource.h])
-AC_TRY_COMPILE([#include <sys/resource.h>],
-[int tmp; tmp=RLIMIT_NPROC;], have_rlimit_as=yes, have_rlimit_as=no)
-if test "$have_rlimit_as" = yes; then
-    AC_MSG_RESULT(yes)
-	AC_DEFINE([HAVE_RLIMIT_NPROC], [1],
-			  [Define to 1 if HAVE_RLIMIT_NPROC is defined in <sys/resource.h>.])
-else
-    AC_MSG_RESULT(no)
-fi
-
-# Check for RLIMIT_AS in sys/resource.h.
-AC_MSG_CHECKING([for RLIMIT_AS in sys/resource.h])
-AC_TRY_COMPILE([#include <sys/resource.h>],
-[int tmp; tmp=RLIMIT_AS;], have_rlimit_as=yes, have_rlimit_as=no)
-if test "$have_rlimit_as" = yes; then
-    AC_MSG_RESULT(yes)
-	AC_DEFINE([HAVE_RLIMIT_AS], [1],
-			  [Define to 1 if HAVE_RLIMIT_AS is defined in <sys/resource.h>.])
-else
-    AC_MSG_RESULT(no)
-fi
-
-# Check for RLIMIT_MEMLOCK in sys/resource.h.
-AC_MSG_CHECKING([for RLIMIT_MEMLOCK in sys/resource.h])
-AC_TRY_COMPILE([#include <sys/resource.h>],
-[int tmp; tmp=RLIMIT_MEMLOCK;], have_rlimit_as=yes, have_rlimit_as=no)
-if test "$have_rlimit_as" = yes; then
-    AC_MSG_RESULT(yes)
-	AC_DEFINE([HAVE_RLIMIT_MEMLOCK], [1],
-			  [Define to 1 if HAVE_RLIMIT_MEMLOCK is defined in <sys/resource.h>.])
-else
-    AC_MSG_RESULT(no)
-fi
-
-# Check for RLIMIT_RSS in sys/resource.h.
-AC_MSG_CHECKING([for RLIMIT_RSS in sys/resource.h])
-AC_TRY_COMPILE([#include <sys/resource.h>],
-[int tmp; tmp=RLIMIT_RSS;], have_rlimit_as=yes, have_rlimit_as=no)
-if test "$have_rlimit_as" = yes; then
-    AC_MSG_RESULT(yes)
-	AC_DEFINE([HAVE_RLIMIT_RSS], [1],
-			  [Define to 1 if HAVE_RLIMIT_RSS is defined in <sys/resource.h>.])
-else
-    AC_MSG_RESULT(no)
-fi
 
 # Check for _nl_msg_cat_cntr symbol
 AC_MSG_CHECKING([for _nl_msg_cat_cntr symbol])