Move to /usr prefix.

- This is much more standard and replaces /image in sysa and is the
  standard in sysc (avoids many issues).
- GCC needs to have a file created for some unknown reason.
- Checksums updated.

sysc/texinfo-6.7/import-gnulib.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+# SPDX-FileCopyrightText: 2021 Andrius Štikonas <andrius@stikonas.eu>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+../gnulib-b81ec69/gnulib-tool --import \
+    --lib=libgnu \
+    --source-base=gnulib/lib \
+    --m4-base=gnulib/m4 \
+    --doc-base=doc \
+    --tests-base=tests \
+    --aux-dir=build-aux \
+    --conditional-dependencies \
+    --no-libtool \
+    --macro-prefix=gl \
+    --no-vc-files \
+    argz \
+    getopt-gnu \
+    gettext-h \
+    iconv \
+    mbchar \
+    mbiter \
+    mbscasecmp \
+    mbschr \
+    mbslen \
+    mbsncasecmp \
+    mbsstr \
+    mbswidth \
+    memrchr \
+    regex \
+    stdarg \
+    strcasestr \
+    strdup-posix \
+    strerror \
+    vasprintf \
+    xalloc