diff --git a/ompi/mca/io/romio/romio/adio/ad_lustre/ad_lustre_rwcontig.c b/ompi/mca/io/romio/romio/adio/ad_lustre/ad_lustre_rwcontig.c
index 5f1c2321ed..cb187a39e9 100644
--- a/ompi/mca/io/romio/romio/adio/ad_lustre/ad_lustre_rwcontig.c
+++ b/ompi/mca/io/romio/romio/adio/ad_lustre/ad_lustre_rwcontig.c
@@ -8,11 +8,6 @@
  *   Copyright (C) 2008 Sun Microsystems, Lustre group
  */
 
-#ifdef _STDC_C99
-#define _XOPEN_SOURCE 600
-#else
-#define _XOPEN_SOURCE 500
-#endif
 #include <unistd.h>
 
 #include <stdlib.h>
diff --git a/ompi/mca/io/romio/romio/adio/ad_xfs/ad_xfs.h b/ompi/mca/io/romio/romio/adio/ad_xfs/ad_xfs.h
index 1a4d4ccc1b..d14858d4aa 100644
--- a/ompi/mca/io/romio/romio/adio/ad_xfs/ad_xfs.h
+++ b/ompi/mca/io/romio/romio/adio/ad_xfs/ad_xfs.h
@@ -8,11 +8,6 @@
 #ifndef AD_XFS_INCLUDE
 #define AD_XFS_INCLUDE
 
-#ifdef _STDC_C99
-#define _XOPEN_SOURCE 600
-#else
-#define _XOPEN_SOURCE 500
-#endif
 #include <unistd.h>
 #include <sys/types.h>
 #include <fcntl.h>
diff --git a/ompi/mca/io/romio/romio/adio/common/ad_read.c b/ompi/mca/io/romio/romio/adio/common/ad_read.c
index 544ccf41f3..19f2908614 100644
--- a/ompi/mca/io/romio/romio/adio/common/ad_read.c
+++ b/ompi/mca/io/romio/romio/adio/common/ad_read.c
@@ -6,11 +6,6 @@
  */
 
 
-#ifdef _STDC_C99
-#define _XOPEN_SOURCE 600
-#else
-#define _XOPEN_SOURCE 500
-#endif
 #include <unistd.h>
 
 #include "adio.h"
diff --git a/ompi/mca/io/romio/romio/adio/common/ad_write.c b/ompi/mca/io/romio/romio/adio/common/ad_write.c
index ad318e4117..34a31d963f 100644
--- a/ompi/mca/io/romio/romio/adio/common/ad_write.c
+++ b/ompi/mca/io/romio/romio/adio/common/ad_write.c
@@ -6,11 +6,6 @@
  */
 
 
-#ifdef _STDC_C99
-#define _XOPEN_SOURCE 600
-#else
-#define _XOPEN_SOURCE 500
-#endif
 #include <unistd.h>
 
 #include "adio.h"
diff --git a/ompi/mca/io/romio/romio/adio/common/utils.c b/ompi/mca/io/romio/romio/adio/common/utils.c
index 98142208da..e8cc6ae109 100644
--- a/ompi/mca/io/romio/romio/adio/common/utils.c
+++ b/ompi/mca/io/romio/romio/adio/common/utils.c
@@ -8,7 +8,6 @@
 #include <adio.h>
 #include <limits.h>
 
-
 /* utility function for creating large contiguous types: algorithim from BigMPI
  * https://github.com/jeffhammond/BigMPI */
 
@@ -78,6 +77,35 @@ int ADIOI_Type_create_hindexed_x(int count,
     return ret;
 }
 
+/* some systems do not have pread/pwrite, or requrie XOPEN_SOURCE set higher
+ * than we would like.  see #1973 */
+#if (HAVE_DECL_PWRITE == 0)
+
+#include <sys/types.h>
+#include <unistd.h>
+
+ssize_t pread(int fd, void *buf, size_t count, off_t offset);
+ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
+
+ssize_t pread(int fd, void *buf, size_t count, off_t offset) {
+    off_t lseek_ret;
+
+    lseek_ret = lseek(fd, offset, SEEK_SET);
+    if (lseek_ret == -1)
+	return lseek_ret;
+    return (read(fd, buf, count));
+}
+
+ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset) {
+    off_t lseek_ret;
+
+    lseek_ret = lseek(fd, offset, SEEK_SET);
+    if (lseek_ret == -1)
+	return lseek_ret;
+    return (write(fd, buf, count));
+}
+#endif
+
 /*
  * vim: ts=8 sts=4 sw=4 noexpandtab
  */
diff --git a/ompi/mca/io/romio/romio/adio/include/adioi.h b/ompi/mca/io/romio/romio/adio/include/adioi.h
index cb9560ce91..eb8efd0fb7 100644
--- a/ompi/mca/io/romio/romio/adio/include/adioi.h
+++ b/ompi/mca/io/romio/romio/adio/include/adioi.h
@@ -1046,3 +1046,10 @@ void *ADIOI_IO_Thread_Func(void *vptr_args);
 
 #endif
 
+
+#if (HAVE_DECL_PWRITE == 0)
+#include <sys/types.h>
+#include <unistd.h>
+ssize_t pread(int fd, void *buf, size_t count, off_t offset);
+ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
+#endif
diff --git a/ompi/mca/io/romio/romio/configure.ac b/ompi/mca/io/romio/romio/configure.ac
index 8570948352..0c56647035 100644
--- a/ompi/mca/io/romio/romio/configure.ac
+++ b/ompi/mca/io/romio/romio/configure.ac
@@ -1477,6 +1477,14 @@ if test "$ac_cv_header_unistd_h" = "yes" ; then
     fi
 fi
 
+# pread and pwrite are useful to ROMIO: if implemented well, they help us avoid
+# an extra system call.  But --enable-strict or CFLAGS="--std=c99" does not
+# expose this feature.  If we define XOPEN_SOURCE in ROMIO, we cause headaches
+# for some versions of lustre, quota.h, and caddr_t.  see if we need to provide
+# our own pread/pwrite
+
+AC_CHECK_DECLS([pwrite])
+
 
 ####################################################################
 # We're about to mess with CC etc.  No more feature tests past here,