Fix error message from 'make html' with no perl.

When the missing tool error messages were adjusted to cover missing
flex, the rule to build HTML documentation (which depends on perl)
got missed.  Redo the error message for this rule in a similar sytle.

diff --git a/Makefile.am b/Makefile.am
index 28ebff90cf526cc50aa933b77ffdde630ad93cf3..72e996bdf136b791938ce87c5780de5dba12768b 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -48,6 +48,13 @@ FLEX_V_  = $(FLEX_V_@AM_DEFAULT_V@)
 FLEX_V_0 = @printf '  %$(DX_ALIGN_V)s %s\n' 'FLEX    ' $<;
 
 TOOL_ERROR = { \
+  echo "ERROR: *** $$tool is missing on your system."; \
+  echo "       *** Because of this, I cannot compile $$toolsrc."; \
+  echo "       *** If $$tool is installed but was not detected by configure,";\
+  echo "       *** consider setting $$toolvar and re-running configure."; \
+  echo "       *** See config.log for more details."; } >&2; false
+
+DEV_TOOL_ERROR = { \
   echo "ERROR: *** $$tool is missing on your system."; \
   echo "       *** Because of this, I cannot compile $$toolsrc, but"; \
   echo "       *** (perhaps because you modified it) the sources appear out"; \
@@ -57,7 +64,7 @@ TOOL_ERROR = { \
 
 src/treefuncs.stamp: src/generate_treefuncs.pl src/treefuncs.def
 if !HAVE_PERL
-       @tool=perl toolvar=PERL toolsrc=src/treefuncs.def; $(TOOL_ERROR)
+       @tool=perl toolvar=PERL toolsrc=src/treefuncs.def; $(DEV_TOOL_ERROR)
 endif
        $(AM_V_at) $(MKDIR_P) $(@D) && touch $@.tmp
        $(AM_V_GEN) (cd $(@D) && \
@@ -68,7 +75,7 @@ endif
 .l.c: ;
 .l.stamp:
 if !HAVE_FLEX
-       @tool=flex toolvar=FLEX toolsrc=$<; $(TOOL_ERROR)
+       @tool=flex toolvar=FLEX toolsrc=$<; $(DEV_TOOL_ERROR)
 endif
        $(AM_V_at) touch $@.tmp
        $(AM_V_at) rm -f $*.h.tmp; mv -f $*.h $*.h.tmp 2>/dev/null; :
@@ -89,7 +96,7 @@ src/lexer.c src/lexer.h: src/lexer.stamp
 html-local: doc/gob2.html
 doc/gob2.html: doc/gob2.1
 if !HAVE_PERL
-       $(PERL_ERROR)
+       @tool=perl toolvar=PERL toolsrc=$@; $(TOOL_ERROR)
 endif
        $(AM_V_GEN) $(PERL) $(top_srcdir)/doc/makehtml.pl <doc/gob2.1 >$@.tmp
        $(AM_V_at) mv -f $@.tmp $@