Patch GCC 4.7.4 for native musl support

Backport upstream patches to enable native musl toolchain support in
GCC. Only the changes required for i386 were taken, excluding
changes for libgo and libfortran.

These patches enable binaries built using gcc and g++ to automatically
use musl's dynamic linker as their interpreter when present during the
build.

sysc/gcc-4.7.4/patches/0008-config-linux.h-add-INCLUDE_DEFAULTS_MUSL_LOCAL.patch

@@ -0,0 +1,21 @@
+SPDX-FileCopyrightText: 2022 Dor Askayo <dor.askayo@gmail.com>
+SPDX-FileCopyrightText: 2015 Doug Evans <dje@google.com>
+
+SPDX-License-Identifier: GPL-2.0-or-later
+
+Backported from upstream commit 755658a56b57beca14b5fb70afdf1e588a058f7f
+
+config/linux.h (INCLUDE_DEFAULTS): Add INCLUDE_DEFAULTS_MUSL_LOCAL.
+
+From-SVN: r229392
+
+--- gcc/config/linux.h
++++ gcc/config/linux.h
+@@ -184,6 +184,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+ #define INCLUDE_DEFAULTS				\
+   {							\
+     INCLUDE_DEFAULTS_MUSL_GPP				\
++    INCLUDE_DEFAULTS_MUSL_LOCAL				\
+     INCLUDE_DEFAULTS_MUSL_PREFIX			\
+     INCLUDE_DEFAULTS_MUSL_CROSS				\
+     INCLUDE_DEFAULTS_MUSL_TOOL				\