package/glibc: switch to using the maintenance branch

glibc upstream has ruled against doing regular point-releases, but they
do have a lot of interesting and important fixes for regressions and
security.

Backporting each patch, or cherry-picking individual patches is off
limits for us, so we just switch to using the currently-latest HEAD of
the maintenance branch instead.

The version number is obtained with:
    $ git describe --match 'glibc-*' --abbrev=40 origin/release/2.26/master

The alternative options were:
  - download the tarball from the git tree
    --> does not work; not an option
  - download the 2.26 tarball, and bundle the individual patches in
    Buildroot
    --> maintenance of patches is a burden; not an option
  - download the 2.26 tarball, maintain the list of patches to download from
    the git tree
    --> not an option for the same reason

So we end up just doing a git clone. The git tree is today about ten
times the size of the tarball, so a rough estimate makes it at about ten
times the download time.

Also upstream doesn't officially provide an https download location [1].
There is one but it's not reliable, sometimes the connection time out and
end-up with a corrupted git repo:

fatal: unable to access 'https://sourceware.org/git/glibc.git/': Failed to connect to sourceware.org port 443: Connection timed out

So switch to using a git mirror from github which is updated once a day [2].
This allow at the same time to clone the git repository faster.

Note: The glibc 2.26 patches are not kept for the arc toolchain since they
are fixing an issue with the new float128 support introduced in x86, x86_64
and powerpc64le.

[1] https://sourceware.org/git/?p=glibc.git;a=summary
[2] https://github.com/bminor/glibc.git

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Romain Naour <romain.naour@openwide.fr>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Evgeniy Didin <didin@synopsys.com>
CC: Alexey Brodkin <abrodkin@synopsys.com>
[Romain: bump 4b692dffb95ac4812b161eb6a16113d7e824982e]
Signed-off-by: Romain Naour <romain.naour@gmail.com>
[yann.morin.1998@free.fr: update comment to never decide on the mirror]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

1 files changed, 0 insertions, 63 deletions

diff --git a/package/glibc/0006-Let-fpclassify-use-the-builtin-when-optimizing-for-s.patch b/package/glibc/0006-Let-fpclassify-use-the-builtin-when-optimizing-for-s.patch
deleted file mode 100644
index 37807c4598..0000000000
--- a/package/glibc/0006-Let-fpclassify-use-the-builtin-when-optimizing-for-s.patch
+++ /dev/null
@@ -1,63 +0,0 @@
-From 33f54cf4f81a51e5c8cbfb2408edd439bdee9435 Mon Sep 17 00:00:00 2001
-From: "Gabriel F. T. Gomes" <gabriel@inconstante.eti.br>
-Date: Wed, 20 Sep 2017 15:10:26 -0300
-Subject: [PATCH] Let fpclassify use the builtin when optimizing for size in
- C++ mode (bug 22146)
-
-When optimization for size is on (-Os), fpclassify does not use the
-type-generic __builtin_fpclassify builtin, instead it uses __MATH_TG.
-However, when library support for float128 is available, __MATH_TG uses
-__builtin_types_compatible_p, which is not available in C++ mode.
-
-On the other hand, libstdc++ undefines (in cmath) many macros from
-math.h, including fpclassify, so that it can provide its own functions.
-However, during its configure tests, libstdc++ just tests for the
-availability of the macros (it does not undefine them, nor does it
-provide its own functions).
-
-Finally, when libstdc++ is configured with optimization for size
-enabled, its configure tests include math.h and get the definition of
-fpclassify that uses __MATH_TG (and __builtin_types_compatible_p).
-Since libstdc++ does not undefine the macros during its configure tests,
-they fail.
-
-This patch lets fpclassify use the builtin in C++ mode, even when
-optimization for size is on.  This allows the configure test in
-libstdc++ to work.
-
-Tested for powerpc64le and x86_64.
-
-	[BZ #22146]
-	math/math.h: Let fpclassify use the builtin in C++ mode, even
-	when optimazing for size.
-
-(cherry picked from commit c5c4a626098ec884b8527356abdf2a4bb7b6bf27)
-
-[Romain rebase on glibc 2.26)
-Signed-off-by: Romain Naour <romain.naour@gmail.com>
----
- math/math.h | 8 +++++++-
- 1 file changed, 7 insertions(+), 1 deletion(-)
-
-diff --git a/math/math.h b/math/math.h
-index 7c0fc6d..f9348ec 100644
---- a/math/math.h
-+++ b/math/math.h
-@@ -402,7 +402,13 @@ enum
- 
- /* Return number of classification appropriate for X.  */
- # if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__			      \
--     && !defined __OPTIMIZE_SIZE__
-+     && (!defined __OPTIMIZE_SIZE__ || defined __cplusplus)
-+     /* The check for __cplusplus allows the use of the builtin, even
-+	when optimization for size is on.  This is provided for
-+	libstdc++, only to let its configure test work when it is built
-+	with -Os.  No further use of this definition of fpclassify is
-+	expected in C++ mode, since libstdc++ provides its own version
-+	of fpclassify in cmath (which undefines fpclassify).  */
- #  define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE,	      \
-      FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
- # else
--- 
-2.9.5
-