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/libunistring-0.9.10/libunistring-0.9.10.sh

@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: 2021 Andrius Štikonas <andrius@stikonas.eu>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+src_prepare() {
+    find . -name '*.info*' -delete
+
+    # libunistring does not specify which gnulib snapshot was used,
+    # pick a random one that works
+    GNULIB_TOOL=../gnulib-52a06cb3/gnulib-tool ./autogen.sh
+
+    # autogen.sh does not regenerate libtool files
+    autoreconf-2.69 -fi
+}
+
+src_configure() {
+    ./configure \
+	--prefix="${PREFIX}" \
+	--libdir="${PREFIX}/lib/musl" \
+	--disable-shared
+}