flex: rework patches to avoid host/target difference

Currently, the target and host flex packages do not behave the same in
terms of patching: the target variant has a patch hook that disables
building the programs (because they are not needed, and do not build
on no-MMU platforms). However, this hook is obviously not executed for
host-flex, because we really want the host flex binary to be built.

In preparation for the introduction of out-of-tree package build, it
is important that we don't do different things in the patch hooks for
the target and host variant of a given package, because the source
tree will be shared between the target and host builds.

To solve this, we introduce a --disable-program configure option,
through a patch to the flex configure.ac and Makefile.am. This patch
makes the current 0001-flex-disable-documentation.patch no longer
needed.

Furthermore, building the documentation is a PITA: flex.1 depends on
configure.ac and a few other files generated during the build. Touching
flex.1 does not work, because automake will forcibly remove the files
when its prerequisites are too old, so pre-requisites of flex.1 will
always be more recent than flex.1. So, we add a patch that adds a
--disable-doc configure option.

Fixes:
    http://autobuild.buildroot.org/results/f70/f70b39632535bb9692d0a032166b2f4104532967/
    http://autobuild.buildroot.org/results/525/52567afdfe7992b3518de0e01227ba14aa300f21/
    [...]

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[yann.morin.1998@free.fr:
  - rebase on-top of master,
  - add patch to not build the documentation, because simply touching
    flex.1 is no longer enough.
  - keep install in target/, for shared builds
]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Adrian Perez de Castro <aperez@igalia.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/package/flex/0003-build-make-it-possible-to-disable-the-build-of-the-d.patch b/package/flex/0003-build-make-it-possible-to-disable-the-build-of-the-d.patch
new file mode 100644
index 0000000000..ffe30d367f
--- /dev/null
+++ b/package/flex/0003-build-make-it-possible-to-disable-the-build-of-the-d.patch
@@ -0,0 +1,58 @@
+From b89b8475a5b2f9444c32f7d254b35968da3c8a23 Mon Sep 17 00:00:00 2001
+From: "Yann E. MORIN" <yann.morin.1998@free.fr>
+Date: Fri, 29 Sep 2017 18:03:51 +0200
+Subject: [PATCH] build: make it possible to disable the build of the
+ documentation
+
+When targetting embedded evices, the documentation is not needed.
+
+Building the documentation default to whether the program is built.
+
+Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
+Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+---
+ Makefile.am  | 8 +++++++-
+ configure.ac | 6 ++++++
+ 2 files changed, 13 insertions(+), 1 deletion(-)
+
+diff --git a/Makefile.am b/Makefile.am
+index fce30b2..ee75b64 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -41,9 +41,15 @@ EXTRA_DIST = \
+ 	.indent.pro \
+ 	autogen.sh
+ 
++MAYBE_SUBDIRS =
++
++if ENABLE_DOC
++MAYBE_SUBDIRS += doc
++endif
++
+ SUBDIRS = \
+ 	src \
+-	doc \
++	$(MAYBE_SUBDIRS) \
+ 	examples \
+ 	po \
+ 	tests \
+diff --git a/configure.ac b/configure.ac
+index c54e98f..b3ae450 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -80,6 +80,12 @@ AC_ARG_ENABLE([program],
+   [], [enable_program=yes])
+ AM_CONDITIONAL([ENABLE_PROGRAM], [test "x$enable_program" = xyes])
+ 
++AC_ARG_ENABLE([doc],
++  [AS_HELP_STRING([--disable-doc],
++                  [do not build the documentation])],
++  [], [enable_doc=${enable_program}])
++AM_CONDITIONAL([ENABLE_DOC], [test "x$enable_doc" = xyes -a "x$enable_program" = xyes])
++
+ # --disable-bootstrap is intended only to workaround problems with bootstrap
+ # (e.g. when cross-compiling flex or when bootstrapping has bugs).
+ # Ideally we should be able to bootstrap even when cross-compiling.
+-- 
+2.11.0
+