Add support for gcc6HEADreplicant-6.0

Without that fix, when building Replicant 6.0 on Trisquel 9 (etiona)
we have the following build error:
    Using [...]/kernel/samsung/smdk4412 as source for kernel
    CHK     include/generated/utsrelease.h
  make[3]: 'include/generated/mach-types.h' is up to date.
    CC      kernel/bounds.s
  In file included from [...]/kernel/samsung/smdk4412/include/linux/compiler.h:48:0,
                   from [...]/kernel/samsung/smdk4412/include/linux/stddef.h:4,
                   from [...]/kernel/samsung/smdk4412/include/linux/posix_types.h:4,
                   from [...]/kernel/samsung/smdk4412/include/linux/types.h:17,
                   from [...]/kernel/samsung/smdk4412/include/linux/page-flags.h:8,
                   from [...]/kernel/samsung/smdk4412/kernel/bounds.c:9:
  [...]/kernel/samsung/smdk4412/include/linux/compiler-gcc.h:99:30:
  fatal error: linux/compiler-gcc6.h: No such file or directory
   #include gcc_header(__GNUC__)
                              ^

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/include/linux/compiler-gcc6.h b/include/linux/compiler-gcc6.h
new file mode 100644
index 00000000000..a3d00d8d316
--- /dev/null
+++ b/include/linux/compiler-gcc6.h
@@ -0,0 +1,66 @@
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-gcc6.h> directly, include <linux/compiler.h> instead."
+#endif
+
+#define __used				__attribute__((__used__))
+#define __must_check			__attribute__((warn_unused_result))
+#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
+
+/* Mark functions as cold. gcc will assume any path leading to a call
+   to them will be unlikely.  This means a lot of manual unlikely()s
+   are unnecessary now for any paths leading to the usual suspects
+   like BUG(), printk(), panic() etc. [but let's keep them for now for
+   older compilers]
+
+   Early snapshots of gcc 4.3 don't support this and we can't detect this
+   in the preprocessor, but we can live with this because they're unreleased.
+   Maketime probing would be overkill here.
+
+   gcc also has a __attribute__((__hot__)) to move hot functions into
+   a special section, but I don't see any sense in this right now in
+   the kernel context */
+#define __cold			__attribute__((__cold__))
+
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
+#ifndef __CHECKER__
+# define __compiletime_warning(message) __attribute__((warning(message)))
+# define __compiletime_error(message) __attribute__((error(message)))
+#endif /* __CHECKER__ */
+
+/*
+ * Mark a position in code as unreachable.  This can be used to
+ * suppress control flow warnings after asm blocks that transfer
+ * control elsewhere.
+ *
+ * Early snapshots of gcc 4.5 don't support this and we can't detect
+ * this in the preprocessor, but we can live with this because they're
+ * unreleased.  Really, we need to have autoconf for the kernel.
+ */
+#define unreachable() __builtin_unreachable()
+
+/* Mark a function definition as prohibited from being cloned. */
+#define __noclone	__attribute__((__noclone__))
+
+/*
+ * Tell the optimizer that something else uses this function or variable.
+ */
+#define __visible __attribute__((externally_visible))
+
+/*
+ * GCC 'asm goto' miscompiles certain code sequences:
+ *
+ *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+ *
+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+ * Fixed in GCC 4.8.2 and later versions.
+ *
+ * (asm goto is automatically volatile - the naming reflects this.)
+ */
+#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+
+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#define __HAVE_BUILTIN_BSWAP16__
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */