From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Korsgaard <peter@korsgaard.com>
Date: Mon, 26 Nov 2018 19:15:36 +0100
Subject: [Buildroot] [PATCH next v6 06/10] package/pkg-generic: adjust
 config scripts tweaks for per-package directories
In-Reply-To: <20181123145815.13008-7-thomas.petazzoni@bootlin.com> (Thomas
 Petazzoni's message of "Fri, 23 Nov 2018 15:58:11 +0100")
References: <20181123145815.13008-1-thomas.petazzoni@bootlin.com>
 <20181123145815.13008-7-thomas.petazzoni@bootlin.com>
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>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@bootlin.com> writes:

 > This commit adjusts the logic in pkg-generic.mk that tweaks the
 > *-config shell scripts installed by various libraries to make it
 > compatible with per-package directories.

 > This requires two fixes:

 >  - replacing $(STAGING_DIR) with a relative path from the config script
 >    to the staging directory, rather than using an absolute path of the
 >    staging directory.

 >    Without this, a *-config script provided by package A, but called
 >    from package B per-package directory will return paths from package A
 >    per-package directory:

 >    $ ./output/per-package/mcrypt/host/usr/<tuple>/sysroot/usr/bin/libmcrypt-config --libs
 >    -L..../output/per-package/libmcrypt/host/usr/<tuple>/sysroot/usr/lib/

 >    The libmcrypt-config script is installed by the libmcrypt package,
 >    and mcrypt is a package that depends on libmcrypt. When we call the
 >    libmcrypt-config script from the mcrypt per-package directory, it
 >    returns a -L flag that points to the libmcrypt per-package
 >    directory.

 >    One might say: but this is OK, since the sysroot of the libmcrypt
 >    per-package directory also contains the libmcrypt library. This is
 >    true, but we encounter a more subtle issue: because -L paths are
 >    considered before standard paths, ld ends up finding libc.so in the
 >    libmcrypt per-package directory. This libc.so file is a linker
 >    script that looks like this:

 >    GROUP ( /lib/libc.so.6 /usr/lib/libc_nonshared.a  AS_NEEDED ( /lib/ld-linux.so.3 ) )

 >    Normally, thanks to ld sysroot awareness, /lib/libc.so.6 in this
 >    script is re-interpreted according to the sysroot. But in this
 >    case, the library is *outside* the compiler sysroot. Remember: we
 >    are using the compiler/linker from the "mcrypt" per-package
 >    directory, but we found "libc.so.6" in the "libmcrypt" per-package
 >    directory.

 >    This causes the linker to really use the /lib/libc.so.6 from the
 >    host machine, obvisouly leading to a build failure such as:

 >    output/per-package/libgcrypt/host/opt/ext-toolchain/bin/../lib/gcc/nios2-linux-gnu/7.3.1/../../../../nios2-linux-gnu/bin/ld: cannot find /lib/libc.so.6
 >    output/per-package/libgcrypt/host/opt/ext-toolchain/bin/../lib/gcc/nios2-linux-gnu/7.3.1/../../../../nios2-linux-gnu/bin/ld: cannot find /usr/lib/libc_nonshared.a
 >    output/per-package/libgcrypt/host/opt/ext-toolchain/bin/../lib/gcc/nios2-linux-gnu/7.3.1/../../../../nios2-linux-gnu/bin/ld: cannot find /lib/ld-linux-nios2.so.1

 >  - Some *-config scripts, such as the apr-1-config script, contain
 >    references to host tools:

 >    CC=".../output/per-package/apr/hosr/bin/arm-linux-gcc"
 >    CCP=".../output/per-package/apr/hosr/bin/arm-linux-cpp"

 >    We also want to replace those with proper relative paths. To
 >    achieve this, we need to also replace $(HOST_DIR) with a relative
 >    path. Since $(STAGING_DIR) is inside $(HOST_DIR), the first
 >    replacement of $(STAGING_DIR) by @STAGING_DIR@ is no longer needed:
 >    replacing $(HOST_DIR) by @HOST_DIR@ is sufficient. We still need to
 >    replace @STAGING_DIR@ by the proper path though, as we introduce
 >    @STAGING_DIR@ references in exec_prefix and prefix variables, as
 >    well as -I and -L flags.

 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
 > Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Committed to next, thanks.

-- 
Bye, Peter Korsgaard