[committed] libstdc++: Regenerate <bits/version.h> in maintainer mode

[committed] libstdc++: Regenerate <bits/version.h> in maintainer mode

[Jonathan Wakely]

Tested x86_64-linux. Pushed to trunk.

I've taken the liberty of assuming that the change to
gcc/doc/install.texi is sufficiently "obviously true" to not require
separate approval.

-- >8 --

This is a generated header but regenerating it requires the manual step
of running 'make -C include update-version' in the libstdc++ build dir.
Make it regenerate automatically when --enable-maintainer-mode is used.

libstdc++-v3/ChangeLog:

	* include/Makefile.am [MAINTAINER_MODE]: Add target to
	automatically update <bits/version.h>.
	* include/Makefile.in: Regenerate.

gcc/ChangeLog:

	* doc/install.texi (Prerequisites): Document use of autogen for
	libstdc++.
---
 gcc/doc/install.texi             | 2 ++
 libstdc++-v3/include/Makefile.am | 6 ++++++
 libstdc++-v3/include/Makefile.in | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index e3650e0c4f4..014ca25aa62 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -545,6 +545,8 @@ Necessary to run @samp{make check} for @file{fixinc}.
 Necessary to regenerate the top level @file{Makefile.in} file from
 @file{Makefile.tpl} and @file{Makefile.def}.
 
+Necessary to regenerate the @file{bits/version.h} header for libstdc++.
+
 @item Flex version 2.5.4 (or later)
 
 Necessary when modifying @file{*.l} files.
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 64152351ed0..cb902de36ae 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -1480,6 +1480,12 @@ update-version:
 	cd ${bits_srcdir} && \
 	autogen version.def
 
+if MAINTAINER_MODE
+# Regenerate it automatically in maintainer mode.
+${bits_srcdir}/version.h: ${bits_srcdir}/version.def ${bits_srcdir}/version.tpl
+	$(MAKE) update-version
+endif
+
 # The real deal.
 install-data-local: install-headers
 install-headers: