toolchain: Add bison

This is required by glibc 2.27

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/patches/glibc/glibc-2.25-gcc-7.patch

@@ -1,23 +0,0 @@
-diff --git a/malloc/hooks.c b/malloc/hooks.c
-index 4398c0a017..2c6cebc889 100644
---- a/malloc/hooks.c
-+++ b/malloc/hooks.c
-@@ -347,11 +347,18 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
-       newmem = _int_realloc (&main_arena, oldp, oldsize, nb);
-     }
- 
-+  DIAG_PUSH_NEEDS_COMMENT;
-+#if __GNUC_PREREQ (7, 0)
-+  /* GCC 7 warns about magic_p may be used uninitialized.  But we never
-+     reach here if magic_p is uninitialized.  */
-+  DIAG_IGNORE_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
-+#endif
-   /* mem2chunk_check changed the magic byte in the old chunk.
-      If newmem is NULL, then the old chunk will still be used though,
-      so we need to invert that change here.  */
-   if (newmem == NULL)
-     *magic_p ^= 0xFF;
-+  DIAG_POP_NEEDS_COMMENT;
- 
-   __libc_lock_unlock (main_arena.mutex);
-