package/gcc: add support for gcc 7

package/gcc: add support for gcc 7

Remove upstream patches:

831-ARM-PR-target-70473-Reduce-size-of-Cortex-A8-automat.patch

870-xtensa-Fix-PR-target-78118.patch

871-xtensa-Fix-PR-target-78603.patch

890-fix-m68k-compile.patch:
https://github.com/gcc-mirror/gcc/commit/1701058da920d27de87dc82e8d327b8ca930e997

892-libgcc-mkmap-symver-support-skip_underscore.patch:
https://github.com/gcc-mirror/gcc/commit/6c8f362e1f17cce05131eb8ff53963d64bc69484

893-libgcc-config-bfin-use-the-generic-linker-version-in.patch:
https://github.com/gcc-mirror/gcc/commit/966d046c08ba50fc988ac614f84f2d49c1546e28

894-libgcc-fix-DWARF-compilation-with-FDPIC-targets.patch:
https://github.com/gcc-mirror/gcc/commit/397d0e43abb943f1fe57801220e7e46bc6636c7c

895-bfin-define-REENTRANT.patch:
https://github.com/gcc-mirror/gcc/commit/da89a4dcdf75bc3134f73520535c949bbbb0c845

940-uclinux-enable-threads.patch:
https://github.com/gcc-mirror/gcc/commit/b9ce54109ec78d18f6123a1e54aae1293bede716

941-mips-Add-support-for-mips-r6-musl.patch:
https://github.com/gcc-mirror/gcc/commit/83717065090bb8b954556d1216dd9dc397dc0243

Remove obsolete patches:

301-missing-execinfo_h.patch: boehm-gc removed from gcc sources:
https://github.com/gcc-mirror/gcc/commit/baf71228766058f5541d929891237d394376c975

830-arm_unbreak_armv4t.patch: SUBTARGET_CPU_DEFAULT removed:
https://github.com/gcc-mirror/gcc/commit/ff3caa3ade14a42d5ab7e81cbd3605fe15aa998d

Add a new patch to allow to build gcc 7.1 without extracting gcc/testsuite
directory.

This new gcc version require a kernel patch [1] to avoid a build issue with
____ilog2_NaN symbol. The following kernel version contain contain already
this patch :
4.11, 4.10.6, 4.9.18, 4.4.57, 3.18.50 and 3.12.73.

To build a toolchain based on gcc 7 and uClibc-ng 1.0.24, the patch [2] is
required to avoid a build issue due to missing aligned_alloc() definition.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=474c90156c8dcc2fa815e6716cc9394d7930cb9c
[2] https://cgit.openadk.org/cgi/cgit/uclibc-ng.git/commit/?id=5b0f49037e8ea8500b05c8f31ee88529ccac4cee

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Tested-by: Theodore Ateba <tf.ateba@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>