Add riscv-gnu-toolchain package. (#32047)

Create a package for riscv-gnu-toolchain, a cross-compilation tool.

var/spack/repos/builtin/packages/riscv-gnu-toolchain/package.py

@@ -0,0 +1,66 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+import shlex
+from subprocess import Popen
+
+from spack.package import *
+
+
+class RiscvGnuToolchain(AutotoolsPackage):
+    """A cross-compilation tool for RISC-V."""
+
+    homepage = "https://spack-tutorial.readthedocs.io/"
+    git = "https://github.com/riscv-collab/riscv-gnu-toolchain.git"
+
+    maintainers = ["wanlinwang"]
+
+    version("develop", branch="master", submodules=True)
+    version("2022.08.08", tag="2022.08.08", submodules=True)
+
+    # Dependencies:
+    depends_on("pkg-config", type="build")
+    depends_on("autoconf", when="@main:", type="build")
+    depends_on("python", type="build")
+    depends_on("gawk", type="build")
+    depends_on("bison", type="build")
+    depends_on("flex@:2.6.1,2.6.4:", type="build")
+    depends_on("texinfo", type="build")
+    depends_on("patchutils", type="build")
+    depends_on("mpc", type="build")
+    depends_on("gmp", type="build")
+    depends_on("mpfr", type="build")
+    depends_on("zlib", type=("build", "link"))
+    depends_on("expat", type=("build", "link"))
+    depends_on("bzip2", type="build")
+    depends_on("gmake@4.3:", type="build")
+
+    conflicts("platform=windows", msg="Windows is not supported.")
+
+    variant(
+        "compiler_type",
+        default="newlib",
+        values=("newlib", "linux"),
+        description="Compiler back-end to build",
+    )
+
+    def build(self, spec, prefix):
+        """Makes the build targets specified by
+        :py:attr:``~.AutotoolsPackage.build_targets``
+        """
+        with working_dir(self.stage.source_path):
+            # modify Makefile not to git init submodules.
+            cmd = "/bin/sed -i.bak -r \
+            '/^# Rule for auto init submodules/,/git submodule update.*$/d' \
+            Makefile"
+            p = Popen(shlex.split(cmd))
+            p.wait()
+            p.communicate()
+
+            params = []
+            if self.spec.satisfies("compiler_type=linux"):
+                params.append("linux")
+
+            make(*params)