toolchains: Flatten riscv-tools submodule

This allows individual components to be better maintained following the
deprecation of riscv-tools.  Eliminate non-essential submodules.

build-static-libfesvr.sh is no longer necessary since libfesvr.a is
built as part of the riscv-isa-sim build.

For simplicity, only riscv-gnu-toolchain is now pre-built instead of the
entirety of riscv-tools.

scripts/build-util.sh

@@ -0,0 +1,89 @@
+# Derived from
+# https://github.com/riscv/riscv-tools/blob/master/build.common
+
+[ -n "${SRCDIR}" ] || exit 1
+
+# Scale number of parallel make jobs by hardware thread count
+ncpu="${NPROC:-$(getconf _NPROCESSORS_ONLN || # GNU
+    getconf NPROCESSORS_ONLN || # *BSD, Solaris
+    nproc --all || # Linux
+    sysctl -n hw.ncpu || # *BSD, OS X
+    :)}" 2>/dev/null
+case ${ncpu} in
+''|*[!0-9]*) ;; # Ignore non-integer values
+*) export MAKEFLAGS="-j ${ncpu} ${MAKEFLAGS}" ;;
+esac
+
+MAKE=$(command -v gmake || command -v make)
+readonly MAKE
+
+
+module_prepare() ( # <submodule> [ignored-submodule..]
+    set -e
+    name=$1
+    shift
+
+    dir="${SRCDIR}/${name}"
+    echo "=>  Starting ${name} build"
+    echo "==>  Initializing ${name} submodule"
+    if [ $# -gt 0 ] ; then
+        git submodule update --init "${dir}"
+        while [ -n "$1" ] ; do
+            git -C "${dir}" config submodule."${1}".update none
+            shift
+        done
+    fi
+    git submodule update --init --recursive "${dir}"
+)
+
+module_run() ( # <submodule> <command..>
+    set -e
+    cd "${SRCDIR}/${1}"
+    shift
+    "$@"
+)
+
+module_make() ( # <submodule> <target..>
+    set -e -o pipefail
+    cd "${SRCDIR}/${1}/build"
+    shift
+    "${MAKE}" "$@" | tee "build-${1:-make}.log"
+)
+
+module_build() ( # <submodule> [configure-arg..]
+    set -e -o pipefail
+    name=$1
+    shift
+
+    cd "${SRCDIR}/${name}"
+
+    if [ -e build ] ; then
+        echo "==>  Removing existing ${name}/build directory"
+        rm -rf build
+    fi
+    if ! [ -e configure ] ; then
+        echo "==>  Updating autoconf files for ${name}"
+        find . -iname configure.ac -type f -print0 |
+        while read -r -d '' file ; do
+            mkdir -p -- "${file%/*}/m4"
+        done
+        autoreconf -i
+    fi
+
+    mkdir -p build
+    cd build
+    {
+        export PATH="${RISCV:+${RISCV}/bin:}${PATH}"
+        echo "==>  Configuring ${name}"
+        ../configure "$@"
+        echo "==>  Building ${name}"
+        "${MAKE}"
+        echo "==>  Installing ${name}"
+        "${MAKE}" install
+    } 2>&1 | tee build.log
+)
+
+module_all() { # <submodule> [configure-arg..]
+    module_prepare "$1"
+    module_build "$@"
+}