new: maintainer mode.

There is now a ./configure --maintainer mode which establishes
a variable called maintainer in config.make, with a y value.

The initial use for maintainer mode will be that the Yacc
parser (the y.tab.c and y.tab.h) files will no longer be
regenerated whenever the parser.y file is newer.

In the following commit, I will add a generated parser.

* Makefile (y.tab.h, y.tab.c): These rules are now only
enabled in maintainer mode via an ifeq.

* configure (maintainer): New variable.
(gen_config_make): Generate maintainer make variable
definition in config.make.

2 files changed, 8 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 29fc9590..8e00b1b5 100644
--- a/Makefile
+++ b/Makefile
@@ -280,6 +280,8 @@ lex.yy.c: $(top_srcdir)parser.l
 	  fi)
 	$(call SH,chmod a-w $@)
 
+ifeq ($(maintainer),y)
+
 y.tab.h: y.tab.c
 	$(call SH,                                              \
 	  if ! [ -e y.tab.h ] ; then                            \
@@ -311,6 +313,8 @@ y.tab.c: $(top_srcdir)parser.y
 	    false ;                                             \
 	  fi)
 
+endif
+
 # Suppress useless sccs id array and unused label warning in byacc otuput.
 # Bison-generated parser also tests for this lint define.
 $(call EACH_CONF,y.tab.o): TXR_CFLAGS += -Dlint
diff --git a/configure b/configure
index 07584383..f86cdccb 100755
--- a/configure
+++ b/configure
@@ -130,6 +130,7 @@ install_prefix=
 bindir='bin'
 datadir='share/txr'
 mandir='share/man'
+maintainer=
 make=
 cross=
 compiler_prefix=
@@ -779,6 +780,9 @@ SHELL := $txr_shell}
 
 txr_ver := $txr_ver
 
+# is this configuration in maintainer mode
+maintainer := $maintainer
+
 # absolute path to source code directory
 top_srcdir := $top_srcdir