configure: META.in template with no hardcoded version number

Author: gasche

.gitignore

@@ -26,3 +26,6 @@ Makefile.config
 /src/glob_lexer.ml
 /ocamlbuild.byte
 /ocamlbuild.native
+
+# generated from META.in
+META

META renamed to META.in

@@ -1,6 +1,7 @@
+#%% see META rule in Makefile
 # Specification for the "ocamlbuild" library
 requires = "unix"
-version = "0.9.0"
+version = "%%VERSION%%"
 description = "ocamlbuild support library"
 archive(byte) = "ocamlbuildlib.cma"
 archive(native) = "ocamlbuildlib.cmxa"

Makefile

@@ -229,14 +229,22 @@ endif
 	echo ']' >> ocamlbuild.install
 	echo >> ocamlbuild.install
 
-install-lib-basics:
+install-lib-basics: META
 	mkdir -p $(INSTALL_LIBDIR)/ocamlbuild
 	$(CP) META src/signatures.mli $(INSTALL_LIBDIR)/ocamlbuild
 
-install-lib-basics-opam:
+install-lib-basics-opam: META
 	echo '  "META"' >> ocamlbuild.install
 	echo '  "src/signatures.mli" {"signatures.mli"}' >> ocamlbuild.install
 
+# %%FOO%% are configuration variables (only %%VERSION%% currently),
+# and #%% comments are removed before installation
+META: META.in VERSION
+	@cat META.in \
+	| sed s/%%VERSION%%/$$(cat VERSION)/ META.in \
+	| grep -v "#%%.*" \
+	> META
+
 install-lib-byte:
 	mkdir -p $(INSTALL_LIBDIR)/ocamlbuild
 	$(CP) $(INSTALL_LIB) $(INSTALL_LIBDIR)/ocamlbuild
@@ -261,7 +269,7 @@ else
 install-lib: install-lib-basics install-lib-byte
 endif
 
-install-lib-findlib:
+install-lib-findlib: META
 ifeq ($(OCAML_NATIVE), true)
 	ocamlfind install ocamlbuild \
 	  META src/signatures.mli $(INSTALL_LIB) $(INSTALL_LIB_OPT)

howto/release.adoc

@@ -93,21 +93,11 @@ release number, so any occurence of +NEXT_RELEASE+ in the development
 repository should be replaced by this version number. There is at
 least one such occurence in the 'Changes' file.
 
-Furthermore, the version coded is hardcoded in some parts of the
-codebase and needs to be updated:
-
-- the 'VERSION' file contains the current version number, with no
-  ending newline
-
-- the 'META' file contains the current version number to inform ocamlfind
-
-You can use +git grep+ to look for all occurrences of +NEXT_RELEASE+
-and a given version number, from the root of the repository:
-
-----
-git grep NEXT_RELEASE
-git grep -F "0.9"
-----
+Furthermore, the version number is written in the 'VERSION' file (no
+ending newline), and it is used to derive the version number at
+installation time -- for example ocamlfind's 'META' file is generated
+from the 'META.in' template. This 'VERSION' file should thus be
+updated.
 
 == Doing the release ==