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, 76 insertions, 0 deletions

diff --git a/package/flex/0002-build-make-it-possible-to-disable-the-build-of-the-f.patch b/package/flex/0002-build-make-it-possible-to-disable-the-build-of-the-f.patch
new file mode 100644
index 0000000000..19f5a772c5
--- /dev/null
+++ b/package/flex/0002-build-make-it-possible-to-disable-the-build-of-the-f.patch
@@ -0,0 +1,76 @@
+From da21733178b34eea303964db5a05e8a3ee4095b4 Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Date: Sat, 26 Aug 2017 15:17:06 +0200
+Subject: [PATCH] build: make it possible to disable the build of the flex
+ program
+
+The flex program uses fork(), which isn't available on noMMU
+systems. However, the libfl library does not use fork(), and be used
+by other programs/libraries.
+
+Therefore, it makes sense to provide an option to disable the build of
+the flex program.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
+
+---
+Submitted-upstream: https://github.com/westes/flex/pull/256
+Refused. We'll have to adapt when they do a new release...
+---
+ Makefile.am     | 2 ++
+ configure.ac    | 6 ++++++
+ doc/Makefile.am | 4 ++++
+ src/Makefile.am | 3 +++
+ 4 files changed, 15 insertions(+)
+
+diff --git a/Makefile.am b/Makefile.am
+index e790e9d..8b57bc9 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -62,8 +62,10 @@ ChangeLog: $(srcdir)/tools/git2cl
+ indent:
+ 	cd src && $(MAKE) $(AM_MAKEFLAGS) indent
+ 
++if ENABLE_PROGRAM
+ install-exec-hook:
+ 	cd $(DESTDIR)$(bindir) && \
+ 		$(LN_S) -f flex$(EXEEXT) flex++$(EXEEXT)
++endif
+ 
+ .PHONY: ChangeLog indent
+diff --git a/configure.ac b/configure.ac
+index 8882016..f49872b 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -75,6 +75,12 @@ AC_ARG_ENABLE([libfl],
+   [], [enable_libfl=yes])
+ AM_CONDITIONAL([ENABLE_LIBFL], [test "x$enable_libfl" = xyes])
+ 
++AC_ARG_ENABLE([program],
++  [AS_HELP_STRING([--disable-program],
++                  [do not build the flex program, only the libfl library])],
++  [], [enable_program=yes])
++AM_CONDITIONAL([ENABLE_PROGRAM], [test "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.
+diff --git a/src/Makefile.am b/src/Makefile.am
+index 0d13a5a..c73bc17 100644
+--- a/src/Makefile.am
++++ b/src/Makefile.am
+@@ -4,7 +4,10 @@ LIBS = @LIBS@
+ 
+ m4 = @M4@
+ 
++if ENABLE_PROGRAM
+ bin_PROGRAMS = flex
++endif
++
+ if ENABLE_BOOTSTRAP
+ noinst_PROGRAMS = stage1flex
+ endif
+-- 
+2.9.4
+