fix(netlib-xblas): build

There's a missing dependency on `m4`.

packages/netlib-xblas/package.py

+# Copyright 2013-2023 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)
+
+from spack.package import *
+
+
+class NetlibXblas(AutotoolsPackage):
+    """XBLAS is a reference implementation for extra precision BLAS.
+
+    XBLAS is a reference implementation for the dense and banded BLAS
+    routines, along with extended and mixed precision version. Extended
+    precision is only used internally; input and output arguments remain
+    the same as in the existing BLAS. Extra precisions is implemented as
+    double-double (i.e., 128-bit total, 106-bit significand). Mixed
+    precision permits some input/output arguments of different types
+    (mixing real and complex) or precisions (mixing single and
+    double). This implementation is proof of concept, and no attempt was
+    made to optimize performance; performance should be as good as
+    straightforward but careful code written by hand."""
+
+    homepage = "https://www.netlib.org/xblas"
+    url = "https://www.netlib.org/xblas/xblas.tar.gz"
+
+    version("1.0.248", sha256="b5fe7c71c2da1ed9bcdc5784a12c5fa9fb417577513fe8a38de5de0007f7aaa1")
+
+    variant("fortran", default=True, description="Build Fortran interfaces")
+    variant("plain_blas", default=True, description="As part of XBLAS, build plain BLAS routines")
+
+    provides("blas", when="+plain_blas")
+
+    depends_on("m4", type="build")
+
+    @property
+    def libs(self):
+        return find_libraries(["libxblas"], root=self.prefix, shared=False, recursive=True)
+
+    def configure_args(self):
+        args = []
+
+        if self.spec.satisfies("~fortran"):
+            args += ["--disable-fortran"]
+
+        if self.spec.satisfies("~plain_blas"):
+            args += ["--disable-plain-blas"]
+
+        return args
+
+    def install(self, spec, prefix):
+        mkdirp(prefix.lib)
+        install("libxblas.a", prefix.lib)
+
+        if self.spec.satisfies("+plain_blas"):
+            # XBLAS should be a drop-in BLAS replacement
+            install("libxblas.a", join_path(prefix.lib, "libblas.a"))
+
+        headers = [
+            "f2c-bridge.h",
+            "blas_dense_proto.h",
+            "blas_enum.h",
+            "blas_extended.h",
+            "blas_extended_private.h",
+            "blas_extended_proto.h",
+            "blas_fpu.h",
+            "blas_malloc.h",
+        ]
+        mkdirp(prefix.include)
+        for h in headers:
+            install(join_path("src", h), prefix.include)
+
+        return