Makefile.in (options.h): Depend on Makefile.

	* Makefile.in (options.h): Depend on Makefile.  Add move-if-change
	to opts.sh command line.
	* opts.sh: Write to temporary files with a move-if-change at the end.

From-SVN: r69200

gcc/Makefile.in

@@ -1416,9 +1416,10 @@ s-specs : Makefile
 
 options.c: $(lang_opt_files) $(srcdir)/opts.sh options.h intl.h
 
-options.h: $(lang_opt_files) $(srcdir)/opts.sh
-	AWK=$(AWK) $(SHELL) $(srcdir)/opts.sh options.c options.h \
-		$(lang_opt_files)
+options.h: $(lang_opt_files) $(srcdir)/opts.sh Makefile
+	AWK=$(AWK) $(SHELL) $(srcdir)/opts.sh \
+               '$(SHELL) $(srcdir)/move-if-change' \
+               options.c options.h $(lang_opt_files)
 
 dumpvers: dumpvers.c
 

gcc/opts.sh

@@ -17,7 +17,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #
-# Usage: opts.sh outfile.c outfile.h file1.opt [file2.opt, ...]
+# Usage: opts.sh moveifchange srcdir outfile.c outfile.h file1.opt [ ...]
 
 # Always operate in the C locale.
 LANG=C
@@ -30,8 +30,11 @@ AWK=${AWK-awk}
 
 SORT=sort		# Could be /bin/sort or /usr/bin/sort
 
+MOVEIFCHANGE=$1; shift
 C_FILE=$1; shift
 H_FILE=$1; shift
+TMP_C_FILE=tmp-${C_FILE}
+TMP_H_FILE=tmp-${H_FILE}
 
 ${AWK} '
 	# Ignore comments and blank lines
@@ -88,13 +91,14 @@ ${AWK} '
 # Dump out an enumeration into a .h file, and an array of options into a
 # C file.  Combine the flags of duplicate options.
     END {
-	c_file = "'${C_FILE}'"
-	h_file = "'${H_FILE}'"
+ 	c_file = "'${TMP_C_FILE}'"
+ 	h_file = "'${TMP_H_FILE}'"
+ 	realh_file = "'${H_FILE}'"
 	comma = ","
 
 	print "/* This file is auto-generated by opts.sh.  */\n" > c_file
 	print "#include <intl.h>"			>> c_file
-	print "#include \"" h_file "\""			>> c_file
+	print "#include \"" realh_file "\""		>> c_file
 	print "#include \"opts.h\"\n"			>> c_file
 	print "const char * const lang_names[] =\n{"	>> c_file
 
@@ -163,3 +167,8 @@ ${AWK} '
 	print "};"					>> c_file
     }
 '
+
+# Copy the newly generated files back to the correct names only if different.
+# This is to prevent a cascade of file rebuilds when not necessary.
+${MOVEIFCHANGE} ${TMP_H_FILE} ${H_FILE}
+${MOVEIFCHANGE} ${TMP_C_FILE} ${C_FILE}