echo empty lines

readline doesn't echo empty lines (when not using a prompt),
so adjust bc to echo empty lines, which is very useful
to delimit interactive input

bc-1.07.1-readline-echo-empty.diff

@@ -0,0 +1,14 @@
+diff -Naur bc-1.07.1/bc/scan.l bc-1.07.1-new/bc/scan.l
+--- bc-1.07.1/bc/scan.l	2017-04-07 22:20:02.000000000 +0000
++++ bc-1.07.1-new/bc/scan.l	2021-08-14 12:12:33.860991777 +0000
+@@ -170,6 +170,10 @@
+       if (rl_len != 1)
+ 	add_history (rl_line); 
+       rl_line[rl_len-1] = '\n';
++      /* readline doesn't echo empty lines without a prompt,
++         so do so here. */
++      if (rl_len == 1)
++        putchar ('\n');
+       fflush (stdout);
+     }
+ 

bc.spec

@@ -1,12 +1,13 @@
 Summary: GNU's bc (a numeric processing language) and dc (a calculator)
 Name: bc
 Version: 1.07.1
-Release: 13%{?dist}
+Release: 14%{?dist}
 License: GPLv2+
 URL: http://www.gnu.org/software/bc/
 Source: http://ftp.gnu.org/gnu/bc/bc-%{version}.tar.gz
 Patch1: bc-1.06-dc_ibase.patch
 Patch2: bc-1.06.95-doc.patch
+Patch3: bc-1.07.1-readline-echo-empty.diff
 BuildRequires:  gcc
 BuildRequires: readline-devel, flex, bison, texinfo, ed
 BuildRequires: make
@@ -40,6 +41,9 @@ rm -f $RPM_BUILD_ROOT/%{_infodir}/dir
 %{_infodir}/*
 
 %changelog
+* Sat Aug 14 2021 Pádraig Brady <P@draigBrady.com> - 1.07.1-14
+- Echo empty lines, useful for delimiting work
+
 * Wed Jul 21 2021 Fedora Release Engineering <releng@fedoraproject.org> - 1.07.1-13
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_35_Mass_Rebuild