lib: utils: Drop dependency on libgcc by importing part of FreeBSD's libquad

We only need libgcc for 64-bit division on RV32. Whilst GCC toolchains
bundle libgcc, Clang toolchains tend not to ship libclang_rt.builtins
given every compiler is a cross-compiler for every target and so you
would need a silly number of builds of it, with only the native library
available; only vendor-provided Clang toolchains specifically for bare
metal cross-compiling are likely to provide it.

Thus, import part of FreeBSD's implementation of the division support
functions needed and stop linking against libgcc.

Signed-off-by: Jessica Clarke <jrtc27@jrtc27.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Anup Patel <anup.patel@wdc.com>

lib/utils/libquad/include/sys/cdefs.h

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Jessica Clarke <jrtc27@jrtc27.com>
+ */
+
+#ifndef __SYS_CDEFS_H__
+#define __SYS_CDEFS_H__
+
+#define __FBSDID(s) struct __hack
+
+#endif

lib/utils/libquad/include/sys/types.h

@@ -0,0 +1,25 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Jessica Clarke <jrtc27@jrtc27.com>
+ */
+
+#ifndef __SYS_TYPES_H__
+#define __SYS_TYPES_H__
+
+#include <sbi/sbi_types.h>
+
+typedef unsigned long u_long;
+
+typedef int64_t quad_t;
+typedef uint64_t u_quad_t;
+
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define _QUAD_LOWWORD 1
+#define _QUAD_HIGHWORD 0
+#else
+#define _QUAD_LOWWORD 0
+#define _QUAD_HIGHWORD 1
+#endif
+
+#endif