support/dependencies: ensure we have 'file' on the host

Recently, the autoconf macros for libtool started using '/usr/bin/file'
to determine the type of library that is generated by the toolchain.
Packages that use this recent version of the libtool autoconf macros
will fail in a rather dramatic way when /usr/bin/file is not present
on the host: the package will still build but no shared library is
generated, which in turn may cause build failures in other packages
that link with it.

For example, libpng's configure determines that it is not possible to
build a shared library on MIPS64 because the expected output from 'file'
is not present. Therefore, only a static libpng.a is built. Later,
bandwithd links with -lpng but it doesn't use the pkg-config's
Private-Libs (because it's not linking statically) and it doesn't have
access to the NEEDED reference from the shared library. Therefore, it
doesn't link with zlib and fails with

    pngrutil.c:(.text+0x55c): undefined reference to `inflate'

We cant use host-file because it is itself an autotools package and is
itself using libtool, so this would be a chicken-n-egg problem. Besides,
the libtool script really wants to call /usr/bin/file, so it would not
even find our host-file anyway.

So, just require that '/usr/bin/file' is present on the host.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

diff --git a/docs/manual/prerequisite.txt b/docs/manual/prerequisite.txt
index 7edad1f6db3e63267dfee85e365f4b78f375f311..ac0ab62e35446be9312d65b3bf16a22c8fb34bed 100644 (file)
--- a/docs/manual/prerequisite.txt
+++ b/docs/manual/prerequisite.txt
@@ -35,6 +35,7 @@ between distributions).
 ** +python+ (version 2.6 or any later)
 ** +unzip+
 ** +rsync+
+** +file+ (must be in +/usr/bin/file+)
 
 * Source fetching tools:
 ** +wget+

diff --git a/support/dependencies/dependencies.sh b/support/dependencies/dependencies.sh
index bfd65960ce8ed5d79de3fdfbc9985bbff7e800ce..168d1960a17709edbe7550c6710e380795436b03 100755 (executable)
--- a/support/dependencies/dependencies.sh
+++ b/support/dependencies/dependencies.sh
@@ -69,6 +69,10 @@ check_prog_host "which"
 # Verify that sed is installed
 check_prog_host "sed"
 
+# 'file' must be present and must be exactly /usr/bin/file,
+# otherwise libtool fails in incomprehensible ways.
+check_prog_host "/usr/bin/file"
+
 # Check make
 MAKE=$(which make 2> /dev/null)
 if [ -z "$MAKE" ] ; then