1 files changed, 7 insertions, 5 deletions

diff --git a/lib/libF77/README b/lib/libF77/README
index b5b0b811036c..a575124bc841 100644
--- a/lib/libF77/README
+++ b/lib/libF77/README
@@ -87,8 +87,10 @@ for use with INTEGER*8.  To use it, you must modify f2c.h to
 declare longint appropriately; then add pow_qq.o to the POW =
 line in the makefile.
 
-If you wish to allow the target of a (character string) concatenation
-to be appear on its right-hand (at the cost of extra overhead for
-all run-time concatenations), change "s_cat.o" to "s_catow.o" in
-the makefile.  Note that the Fortran 77 Standard explicitly forbids
-the target of a concatenation from appearing on its right-hand side.
+Following Fortran 90, s_cat.c and s_copy.c allow the target of a
+(character string) assignment to be appear on its right-hand, at
+the cost of some extra overhead for all run-time concatenations.
+If you prefer the  extra efficiency that comes with the Fortran 77
+requirement that the left-hand side of a character assignment not
+be involved in the right-hand side, compile s_cat.c and s_copy.c
+with -DNO_OVERWRITE .