Merge branch 'sl/autoconf'

* sl/autoconf:
  build: reconfigure automatically if configure.ac changes
  build: "make clean" should not remove configure-generated files
  autoconf: use AC_CONFIG_COMMANDS instead of ad-hoc 'config.mak.append'
  autoconf: remove few redundant semicolons
  autoconf: remove some redundant shell indirections
  autoconf: GIT_CONF_APPEND_LINE -> GIT_CONF_SUBST
  autoconf: GIT_CONF_APPEND_LINE: change signature

2 files changed, 46 insertions, 27 deletions

diff --git a/Makefile b/Makefile
index 285c660e14..f4e8fac491 100644
--- a/Makefile
+++ b/Makefile
@@ -2158,6 +2158,18 @@ configure: configure.ac GIT-VERSION-FILE
 	autoconf -o $@ $<+ && \
 	$(RM) $<+
 
+ifdef AUTOCONFIGURED
+config.status: configure
+	$(QUIET_GEN)if test -f config.status; then \
+	  ./config.status --recheck; \
+	else \
+	  ./configure; \
+	fi
+reconfigure config.mak.autogen: config.status
+	$(QUIET_GEN)./config.status
+.PHONY: reconfigure # This is a convenience target.
+endif
+
 XDIFF_OBJS += xdiff/xdiffi.o
 XDIFF_OBJS += xdiff/xprepare.o
 XDIFF_OBJS += xdiff/xutils.o
@@ -2742,6 +2754,9 @@ dist-doc:
 
 distclean: clean
 	$(RM) configure
+	$(RM) config.log config.status config.cache
+	$(RM) config.mak.autogen config.mak.append
+	$(RM) -r autom4te.cache
 
 profile-clean:
 	$(RM) $(addsuffix *.gcda,$(addprefix $(PROFILE_DIR)/, $(object_dirs)))
@@ -2756,8 +2771,6 @@ clean: profile-clean
 	$(RM) -r $(dep_dirs)
 	$(RM) -r po/build/
 	$(RM) *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h $(ETAGS_TARGET) tags cscope*
-	$(RM) -r autom4te.cache
-	$(RM) config.log config.mak.autogen config.mak.append config.status config.cache
 	$(RM) -r $(GIT_TARNAME) .doc-tmp-dir
 	$(RM) $(GIT_TARNAME).tar.gz git-core_$(GIT_VERSION)-*.tar.gz
 	$(RM) $(htmldocs).tar.gz $(manpages).tar.gz
diff --git a/configure.ac b/configure.ac
index 4e9012f49b..df7e376590 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,11 +3,24 @@
 
 ## Definitions of private macros.
 
-# GIT_CONF_APPEND_LINE(LINE)
-# --------------------------
-# Append LINE to file ${config_append}
-AC_DEFUN([GIT_CONF_APPEND_LINE],
-         [echo "$1" >> "${config_append}"])
+# GIT_CONF_SUBST(VAL, VAR)
+# ------------------------
+# Cause the line "VAR=VAL" to be eventually appended to ${config_file}.
+AC_DEFUN([GIT_CONF_SUBST],
+   [AC_REQUIRE([GIT_CONF_SUBST_INIT])
+   config_appended_defs="$config_appended_defs${newline}$1=$2"])
+
+# GIT_CONF_SUBST_INIT
+# -------------------
+# Prepare shell variables and autoconf machine required by later calls
+# to GIT_CONF_SUBST.
+AC_DEFUN([GIT_CONF_SUBST_INIT],
+    [config_appended_defs=; newline='
+'
+    AC_CONFIG_COMMANDS([$config_file],
+                       [echo "$config_appended_defs" >> "$config_file"],
+                       [config_file=$config_file
+                        config_appended_defs="$config_appended_defs"])])
 
 # GIT_ARG_SET_PATH(PROGRAM)
 # -------------------------
@@ -29,13 +42,12 @@ AC_DEFUN([GIT_ARG_SET_PATH],
 # --without-PROGRAM is used.
 AC_DEFUN([GIT_CONF_APPEND_PATH],
     [m4_pushdef([GIT_UC_PROGRAM], m4_toupper([$1]))dnl
-    PROGRAM=GIT_UC_PROGRAM
     if test "$withval" = "no"; then
 	if test -n "$2"; then
 		GIT_UC_PROGRAM[]_PATH=$withval
-		AC_MSG_NOTICE([Disabling use of ${PROGRAM}])
-		GIT_CONF_APPEND_LINE(NO_${PROGRAM}=YesPlease)
-		GIT_CONF_APPEND_LINE(${PROGRAM}_PATH=)
+		AC_MSG_NOTICE([Disabling use of GIT_UC_PROGRAM])
+		GIT_CONF_SUBST([NO_]GIT_UC_PROGRAM, [YesPlease])
+		GIT_CONF_SUBST(GIT_UC_PROGRAM[]_PATH, [])
 	else
 		AC_MSG_ERROR([You cannot use git without $1])
 	fi
@@ -45,7 +57,7 @@ AC_DEFUN([GIT_CONF_APPEND_PATH],
 	else
 		GIT_UC_PROGRAM[]_PATH=$withval
 		AC_MSG_NOTICE([Setting GIT_UC_PROGRAM[]_PATH to $withval])
-		GIT_CONF_APPEND_LINE(${PROGRAM}_PATH=$withval)
+		GIT_CONF_SUBST(GIT_UC_PROGRAM[]_PATH, [$withval])
 	fi
     fi
     m4_popdef([GIT_UC_PROGRAM])])
@@ -58,7 +70,6 @@ AC_DEFUN([GIT_CONF_APPEND_PATH],
 # * Unset NO_PACKAGE for --with-PACKAGE without ARG
 AC_DEFUN([GIT_PARSE_WITH],
     [m4_pushdef([GIT_UC_PACKAGE], m4_toupper([$1]))dnl
-    PACKAGE=GIT_UC_PACKAGE
     if test "$withval" = "no"; then
 	NO_[]GIT_UC_PACKAGE=YesPlease
     elif test "$withval" = "yes"; then
@@ -67,7 +78,7 @@ AC_DEFUN([GIT_PARSE_WITH],
 	NO_[]GIT_UC_PACKAGE=
 	GIT_UC_PACKAGE[]DIR=$withval
 	AC_MSG_NOTICE([Setting GIT_UC_PACKAGE[]DIR to $withval])
-	GIT_CONF_APPEND_LINE(${PACKAGE}DIR=$withval)
+	GIT_CONF_SUBST(GIT_UC_PACKAGE[DIR], [$withval])
     fi
     m4_popdef([GIT_UC_PACKAGE])])
 
@@ -87,7 +98,7 @@ AC_DEFUN([GIT_PARSE_WITH_SET_MAKE_VAR],
 		     [a value for $1 ($2).  Maybe you do...?])
   fi
   AC_MSG_NOTICE([Setting $2 to $withval])
-  GIT_CONF_APPEND_LINE($2=$withval)
+  GIT_CONF_SUBST([$2], [$withval])
  fi)])# GIT_PARSE_WITH_SET_MAKE_VAR
 
 #
@@ -135,10 +146,9 @@ AC_INIT([git], [@@GIT_VERSION@@], [git@vger.kernel.org])
 AC_CONFIG_SRCDIR([git.c])
 
 config_file=config.mak.autogen
-config_append=config.mak.append
 config_in=config.mak.in
 
-echo "# ${config_append}.  Generated by configure." > "${config_append}"
+GIT_CONF_SUBST([AUTOCONFIGURED], [YesPlease])
 
 # Directories holding "saner" versions of common or POSIX binaries.
 AC_ARG_WITH([sane-tool-path],
@@ -150,7 +160,7 @@ AC_ARG_WITH([sane-tool-path],
   else
     AC_MSG_NOTICE([Setting SANE_TOOL_PATH to '$withval'])
   fi
-  GIT_CONF_APPEND_LINE([SANE_TOOL_PATH=$withval])],
+  GIT_CONF_SUBST([SANE_TOOL_PATH], [$withval])],
   [# If the "--with-sane-tool-path" option was not given, don't touch
    # SANE_TOOL_PATH here, but let defaults in Makefile take care of it.
    # This should minimize spurious differences in the behaviour of the
@@ -169,7 +179,7 @@ AC_ARG_WITH([lib],
   else
 	lib=$withval
 	AC_MSG_NOTICE([Setting lib to '$lib'])
-	GIT_CONF_APPEND_LINE(lib=$withval)
+	GIT_CONF_SUBST([lib], [$withval])
   fi])
 
 if test -z "$lib"; then
@@ -205,7 +215,7 @@ AC_ARG_ENABLE([jsmin],
 [
   JSMIN=$enableval;
   AC_MSG_NOTICE([Setting JSMIN to '$JSMIN' to enable JavaScript minifying])
-  GIT_CONF_APPEND_LINE(JSMIN=$enableval);
+  GIT_CONF_SUBST([JSMIN], [$enableval])
 ])
 
 # Define option to enable CSS minification
@@ -215,7 +225,7 @@ AC_ARG_ENABLE([cssmin],
 [
   CSSMIN=$enableval;
   AC_MSG_NOTICE([Setting CSSMIN to '$CSSMIN' to enable CSS minifying])
-  GIT_CONF_APPEND_LINE(CSSMIN=$enableval);
+  GIT_CONF_SUBST([CSSMIN], [$enableval])
 ])
 
 ## Site configuration (override autodetection)
@@ -256,7 +266,7 @@ AS_HELP_STRING([],           [ARG can be also prefix for libpcre library and hea
 	USE_LIBPCRE=YesPlease
 	LIBPCREDIR=$withval
 	AC_MSG_NOTICE([Setting LIBPCREDIR to $withval])
-	GIT_CONF_APPEND_LINE(LIBPCREDIR=$withval)
+	GIT_CONF_SUBST([LIBPCREDIR], [$withval])
     fi)
 #
 # Define NO_CURL if you do not have curl installed.  git-http-pull and
@@ -1043,9 +1053,5 @@ AC_SUBST(PTHREAD_LIBS)
 AC_SUBST(NO_PTHREADS)
 
 ## Output files
-AC_CONFIG_FILES(["${config_file}":"${config_in}":"${config_append}"])
+AC_CONFIG_FILES(["${config_file}":"${config_in}"])
 AC_OUTPUT
-
-
-## Cleanup
-rm -f "${config_append}"