Fix build errors related to doc/idn2--help.texi. Closes: #93.

With older makeinfo, this would manifest itself by looking for
idn2-help.texi instead.  Further, some BSD grep implementations did
not like the \+ regexp command, so we now rely on the (apparently)
more portable * regexp command.  Reported-By: David Gessel.  See
<#93>.

.gitignore

@@ -33,7 +33,7 @@
 /doc/decode.c
 /doc/example-toascii.c
 /doc/example-tounicode.c
-/doc/idn2--help.texi
+/doc/idn2-help.texi
 /doc/idn2.1
 /doc/libidn2.aux
 /doc/libidn2.cp

NEWS

@@ -6,6 +6,13 @@ Libidn2 NEWS -- History of user-visible changes.                -*- outline -*-
 Now U+32FF works.  Fixes
 <https://gitlab.com/libidn/libidn2/-/issues/77>.
 
+** Fix build errors related to doc/idn2--help.texi.
+With older makeinfo, this would manifest itself by looking for
+idn2-help.texi instead.  Further, some BSD grep implementations did
+not like the \+ regexp command, so we now rely on the (apparently)
+more portable * regexp command.  Reported-By: David Gessel.  See
+<https://gitlab.com/libidn/libidn2/-/issues/93>.
+
 * Noteworthy changes in release 2.3.1 (2021-05-12) [stable]
 
 ** Implement full roundtrip for lookup functionality

doc/Makefile.am

@@ -19,7 +19,7 @@ EXTRA_DIST = gdoc libidn2.html libidn2.pdf texinfo.css idn2.h2m
 BUILT_SOURCES = idn2.1
 info_TEXINFOS = libidn2.texi
 libidn2_TEXINFOS = libidn2.texi example-tounicode.c example-toascii.c	\
-	decode.c lookup.c register.c $(gdoc_TEXINFOS) idn2--help.texi
+	decode.c lookup.c register.c $(gdoc_TEXINFOS) idn2-help.texi
 
 AM_MAKEINFOHTMLFLAGS = $(AM_MAKEINFOFLAGS) \
 	--no-split --number-sections --css-include=texinfo.css
@@ -50,9 +50,9 @@ idn2.1: idn2.h2m $(top_srcdir)/src/idn2.c $(top_srcdir)/src/idn2.ggo \
 	$(HELP2MAN) --include=$(srcdir)/idn2.h2m \
 		--output=$@ $(top_builddir)/src/idn2$(EXEEXT)
 
-idn2--help.texi: $(top_srcdir)/src/idn2.c
-	$(top_builddir)/src/idn2$(EXEEXT) --help | $(GREP) '^ \+-' > tmp
-	mv tmp idn2--help.texi
+idn2-help.texi: $(top_srcdir)/src/idn2.c
+	$(top_builddir)/src/idn2$(EXEEXT) --help | $(GREP) '^  *-' > tmp
+	mv tmp idn2-help.texi
 
 MAINTAINERCLEANFILES = $(dist_man_MANS) decode.c example-tounicode.c example-toascii.c lookup.c \
 	register.c stamp-vti version.texi

doc/libidn2.texi

@@ -486,7 +486,7 @@ To process a string that starts with @code{-}, for example
 @section Options
 @code{idn2} recognizes these commands:
 
-@verbatiminclude idn2--help.texi
+@verbatiminclude idn2-help.texi
 
 @section Environment Variables