diff --git a/.github/workflows/test-action.yaml b/.github/workflows/test-action.yaml
index fb97a78..f2898a4 100644
--- a/.github/workflows/test-action.yaml
+++ b/.github/workflows/test-action.yaml
@@ -44,4 +44,4 @@ jobs:
           upstream: https://github.com/researchapps/spack
           branch: develop
           pull_request: false
-          open_issue: false
+          open_issue: false
\ No newline at end of file
diff --git a/packages/m4/checks-198.sysval.1.patch b/packages/m4/checks-198.sysval.1.patch
new file mode 100644
index 0000000..3731fd8
--- /dev/null
+++ b/packages/m4/checks-198.sysval.1.patch
@@ -0,0 +1,27 @@
+From a1354086d92efa06f5866b008a019f6d801367ca Mon Sep 17 00:00:00 2001
+From: Eric Blake <eblake@redhat.com>
+Date: Sat, 29 May 2021 06:51:53 -0500
+Subject: doc: Minor formatting tweak.
+
+* doc/m4.texi (Sysval): Fix overfull /hbox.
+---
+ doc/m4.texi | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/doc/m4.texi b/doc/m4.texi
+index 94ac851d..247f2be5 100644
+--- a/doc/m4.texi
++++ b/doc/m4.texi
+@@ -6756,7 +6756,8 @@ ifdef(`__unix__', ,
+ ')m4exit(`77')')dnl
+ changequote(`[', `]')
+ @result{}
+-syscmd([/bin/sh -c 'kill -9 $$'; st=$?; test $st = 137 || test $st = 265])
++syscmd([/bin/sh -c 'kill -9 $$'; st=$?;
++test $st = 137 || test $st = 265])
+ @result{}
+ ifelse(sysval, [0], , [errprint([ skipping: shell does not send signal 9
+ ])m4exit([77])])dnl
+-- 
+cgit v1.2.1
+
diff --git a/packages/m4/checks-198.sysval.2.patch b/packages/m4/checks-198.sysval.2.patch
new file mode 100644
index 0000000..e71273e
--- /dev/null
+++ b/packages/m4/checks-198.sysval.2.patch
@@ -0,0 +1,31 @@
+From cd7f4d153ccccf601751e9fa82424412f6ecfc96 Mon Sep 17 00:00:00 2001
+From: Eric Blake <eblake@redhat.com>
+Date: Tue, 1 Jun 2021 08:10:51 -0500
+Subject: tests: Fix 198.sysval
+
+In my attempt to avoid test failures on Haiku, I caused test failures
+on platforms where sh is noisy when reporting a killed sub-process.
+
+* doc/m4.texi (Sysval): Avoid stderr noise during test.
+Fixes: 17011ea76a (tests: Skip signal detection on Haiku)
+Fixes: https://lists.gnu.org/archive/html/bug-m4/2021-05/msg00029.html
+---
+ doc/m4.texi | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/doc/m4.texi b/doc/m4.texi
+index 247f2be5..3b833b2a 100644
+--- a/doc/m4.texi
++++ b/doc/m4.texi
+@@ -6756,7 +6756,7 @@ ifdef(`__unix__', ,
+ ')m4exit(`77')')dnl
+ changequote(`[', `]')
+ @result{}
+-syscmd([/bin/sh -c 'kill -9 $$'; st=$?;
++syscmd([@{ /bin/sh -c 'kill -9 $$'; @} 2>/dev/null; st=$?;
+ test $st = 137 || test $st = 265])
+ @result{}
+ ifelse(sysval, [0], , [errprint([ skipping: shell does not send signal 9
+-- 
+cgit v1.2.1
+
diff --git a/packages/m4/gnulib-pgi.patch b/packages/m4/gnulib-pgi.patch
new file mode 100644
index 0000000..059d897
--- /dev/null
+++ b/packages/m4/gnulib-pgi.patch
@@ -0,0 +1,195 @@
+Port to PGI 16.10 x86-64
+
+This patch fixes one real bug in gl_anylinked_list2.h, along with some minor
+glitches that are not bugs. It does not silence PGI's thousands of bogus
+warnings when compiling test-intprops.c. Fortunately, the warnings do not
+cause a failure.
+
+* lib/c-ctype.h (_C_CTYPE_LOWER_A_THRU_F_N, _C_CTYPE_LOWER_N): Rename parameter
+  to avoid PGI warning about '#define f(n) 'n''. My goodness, PGI goes back a
+  long ways - this predates C89!
+* lib/gl_anylinked_list2.h (ASYNCSAFE): Fix bug caught by PGI. For example,
+  ASYNCSAFE (const void *) should expand to 'const void *volatile', not to
+  'volatile const void *'.
+* lib/spawn.in.h (POSIX_SPAWN_USEVFORK): Don't define if already defined.
+* lib/verify.h (verify) [!__GNUC__]: Use shorter albeit meaningless string to
+  bypass silly compiler limits.
+* tests/infinity.h (Infinityf, Infinityd, Infinityl) [__PGI]:
+* tests/nan.h (NaNf, NaNd, NaNl): Use static functions to avoid misguided
+  compiler diagnostics. Is there some reason we don’t use static functions
+  on all platforms?
+
+diff --git a/lib/c-ctype.h b/lib/c-ctype.h
+index bdca1f1..ec6a3a0 100644
+--- a/lib/c-ctype.h
++++ b/lib/c-ctype.h
+@@ -115,16 +115,16 @@ extern "C" {
+ 
+ /* Cases for lowercase hex letters, and lowercase letters, all offset by N.  */
+ 
+-#define _C_CTYPE_LOWER_A_THRU_F_N(n) \
+-   case 'a' + (n): case 'b' + (n): case 'c' + (n): case 'd' + (n): \
+-   case 'e' + (n): case 'f' + (n)
+-#define _C_CTYPE_LOWER_N(n) \
+-   _C_CTYPE_LOWER_A_THRU_F_N(n): \
+-   case 'g' + (n): case 'h' + (n): case 'i' + (n): case 'j' + (n): \
+-   case 'k' + (n): case 'l' + (n): case 'm' + (n): case 'n' + (n): \
+-   case 'o' + (n): case 'p' + (n): case 'q' + (n): case 'r' + (n): \
+-   case 's' + (n): case 't' + (n): case 'u' + (n): case 'v' + (n): \
+-   case 'w' + (n): case 'x' + (n): case 'y' + (n): case 'z' + (n)
++#define _C_CTYPE_LOWER_A_THRU_F_N(N) \
++   case 'a' + (N): case 'b' + (N): case 'c' + (N): case 'd' + (N): \
++   case 'e' + (N): case 'f' + (N)
++#define _C_CTYPE_LOWER_N(N) \
++   _C_CTYPE_LOWER_A_THRU_F_N(N): \
++   case 'g' + (N): case 'h' + (N): case 'i' + (N): case 'j' + (N): \
++   case 'k' + (N): case 'l' + (N): case 'm' + (N): case 'n' + (N): \
++   case 'o' + (N): case 'p' + (N): case 'q' + (N): case 'r' + (N): \
++   case 's' + (N): case 't' + (N): case 'u' + (N): case 'v' + (N): \
++   case 'w' + (N): case 'x' + (N): case 'y' + (N): case 'z' + (N)
+ 
+ /* Cases for hex letters, digits, lower, punct, and upper.  */
+ 
+diff --git a/lib/gl_anylinked_list2.h b/lib/gl_anylinked_list2.h
+index c249f31..4545da9 100644
+--- a/lib/gl_anylinked_list2.h
++++ b/lib/gl_anylinked_list2.h
+@@ -29,7 +29,7 @@
+    and we use 'volatile' assignments to prevent the compiler from reordering
+    such assignments.  */
+ #ifdef SIGNAL_SAFE_LIST
+-# define ASYNCSAFE(type) *(volatile type *)&
++# define ASYNCSAFE(type) *(type volatile *)&
+ #else
+ # define ASYNCSAFE(type)
+ #endif
+diff --git a/lib/spawn.in.h b/lib/spawn.in.h
+index e8116f9..b4b9197 100644
+--- a/lib/spawn.in.h
++++ b/lib/spawn.in.h
+@@ -142,7 +142,8 @@ typedef struct
+ # endif
+ #endif
+ /* A GNU extension.  Use the next free bit position.  */
+-#define POSIX_SPAWN_USEVFORK \
++#ifndef POSIX_SPAWN_USEVFORK
++# define POSIX_SPAWN_USEVFORK \
+   ((POSIX_SPAWN_RESETIDS | (POSIX_SPAWN_RESETIDS - 1)                     \
+     | POSIX_SPAWN_SETPGROUP | (POSIX_SPAWN_SETPGROUP - 1)                 \
+     | POSIX_SPAWN_SETSIGDEF | (POSIX_SPAWN_SETSIGDEF - 1)                 \
+@@ -152,6 +153,7 @@ typedef struct
+     | POSIX_SPAWN_SETSCHEDULER                                            \
+     | (POSIX_SPAWN_SETSCHEDULER > 0 ? POSIX_SPAWN_SETSCHEDULER - 1 : 0))  \
+    + 1)
++#endif
+ #if !GNULIB_defined_verify_POSIX_SPAWN_USEVFORK_no_overlap
+ typedef int verify_POSIX_SPAWN_USEVFORK_no_overlap
+             [(((POSIX_SPAWN_RESETIDS | POSIX_SPAWN_SETPGROUP
+diff --git a/lib/verify.h b/lib/verify.h
+index dcaf7ca..dcba9c8 100644
+--- a/lib/verify.h
++++ b/lib/verify.h
+@@ -248,7 +248,12 @@ template <int w>
+ /* Verify requirement R at compile-time, as a declaration without a
+    trailing ';'.  */
+ 
+-#define verify(R) _GL_VERIFY (R, "verify (" #R ")")
++#ifdef __GNUC__
++# define verify(R) _GL_VERIFY (R, "verify (" #R ")")
++#else
++/* PGI barfs if R is long.  Play it safe.  */
++# define verify(R) _GL_VERIFY (R, "verify (...)")
++#endif
+ 
+ #ifndef __has_builtin
+ # define __has_builtin(x) 0
+diff --git a/tests/infinity.h b/tests/infinity.h
+index 431f700..ef5d3bd 100644
+--- a/tests/infinity.h
++++ b/tests/infinity.h
+@@ -18,8 +18,9 @@
+ /* Infinityf () returns a 'float' +Infinity.  */
+ 
+ /* The Microsoft MSVC 9 compiler chokes on the expression 1.0f / 0.0f.
+-   The IBM XL C compiler on z/OS complains.  */
+-#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++   The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
++#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__) || defined __PGI
+ static float
+ Infinityf ()
+ {
+@@ -34,8 +35,9 @@ Infinityf ()
+ /* Infinityd () returns a 'double' +Infinity.  */
+ 
+ /* The Microsoft MSVC 9 compiler chokes on the expression 1.0 / 0.0.
+-   The IBM XL C compiler on z/OS complains.  */
+-#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++   The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
++#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__) || defined __PGI
+ static double
+ Infinityd ()
+ {
+@@ -50,8 +52,9 @@ Infinityd ()
+ /* Infinityl () returns a 'long double' +Infinity.  */
+ 
+ /* The Microsoft MSVC 9 compiler chokes on the expression 1.0L / 0.0L.
+-   The IBM XL C compiler on z/OS complains.  */
+-#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++   The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
++#if defined _MSC_VER || (defined __MVS__ && defined __IBMC__) || defined __PGI
+ static long double
+ Infinityl ()
+ {
+diff --git a/tests/nan.h b/tests/nan.h
+index 48236b5..b5a0f29 100644
+--- a/tests/nan.h
++++ b/tests/nan.h
+@@ -25,8 +25,11 @@
+ /* NaNf () returns a 'float' not-a-number.  */
+ 
+ /* The Compaq (ex-DEC) C 6.4 compiler and the Microsoft MSVC 9 compiler choke
+-   on the expression 0.0 / 0.0.  The IBM XL C compiler on z/OS complains.  */
+-#if defined __DECC || defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++   on the expression 0.0 / 0.0.  The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
++#if (defined __DECC || defined _MSC_VER \
++     || (defined __MVS__ && defined __IBMC__)   \
++     || defined __PGI)
+ static float
+ NaNf ()
+ {
+@@ -41,8 +44,11 @@ NaNf ()
+ /* NaNd () returns a 'double' not-a-number.  */
+ 
+ /* The Compaq (ex-DEC) C 6.4 compiler and the Microsoft MSVC 9 compiler choke
+-   on the expression 0.0 / 0.0.  The IBM XL C compiler on z/OS complains.  */
+-#if defined __DECC || defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++   on the expression 0.0 / 0.0.  The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
++#if (defined __DECC || defined _MSC_VER \
++     || (defined __MVS__ && defined __IBMC__)   \
++     || defined __PGI)
+ static double
+ NaNd ()
+ {
+@@ -59,14 +65,15 @@ NaNd ()
+ /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
+    runtime type conversion.
+    The Microsoft MSVC 9 compiler chokes on the expression 0.0L / 0.0L.
+-   The IBM XL C compiler on z/OS complains.  */
++   The IBM XL C compiler on z/OS complains.
++   PGI 16.10 complains.  */
+ #ifdef __sgi
+ static long double NaNl ()
+ {
+   double zero = 0.0;
+   return zero / zero;
+ }
+-#elif defined _MSC_VER || (defined __MVS__ && defined __IBMC__)
++#elif defined _MSC_VER || (defined __MVS__ && defined __IBMC__) || defined __PGI
+ static long double
+ NaNl ()
+ {
diff --git a/packages/m4/nvhpc-1.4.19.patch b/packages/m4/nvhpc-1.4.19.patch
new file mode 100644
index 0000000..ee9398b
--- /dev/null
+++ b/packages/m4/nvhpc-1.4.19.patch
@@ -0,0 +1,14 @@
+--- a/lib/intprops.h
++++ b/lib/intprops.h
+@@ -232,9 +232,9 @@
+    (A, B, P) work when P is non-null.  */
+ /* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x,
+    see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98269>.  */
+-#if 7 <= __GNUC__ && !defined __ICC
++#if 7 <= __GNUC__ && !defined __ICC && !defined __NVCOMPILER
+ # define _GL_HAS_BUILTIN_ADD_OVERFLOW 1
+-#elif defined __has_builtin
++#elif defined __has_builtin && !defined __NVCOMPILER
+ # define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow)
+ #else
+ # define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
diff --git a/packages/m4/nvhpc-long-width.patch b/packages/m4/nvhpc-long-width.patch
new file mode 100644
index 0000000..1dceb3a
--- /dev/null
+++ b/packages/m4/nvhpc-long-width.patch
@@ -0,0 +1,17 @@
+--- a/lib/regex_internal.h
++++ b/lib/regex_internal.h
+@@ -39,6 +39,14 @@
+ #include <intprops.h>
+ #include <verify.h>
+ 
++#ifndef __LONG_WIDTH__
++#if LONG_WIDTH
++#define __LONG_WIDTH__ LONG_WIDTH
++#else
++#define __LONG_WIDTH__ __WORDSIZE
++#endif
++#endif
++
+ #if defined DEBUG && DEBUG != 0
+ # include <assert.h>
+ # define DEBUG_ASSERT(x) assert (x)
diff --git a/packages/m4/nvhpc.patch b/packages/m4/nvhpc.patch
new file mode 100644
index 0000000..2fc74f4
--- /dev/null
+++ b/packages/m4/nvhpc.patch
@@ -0,0 +1,34 @@
+--- a/lib/xalloc-oversized.h	2020-08-07 11:04:56.154698639 -0700
++++ b/lib/xalloc-oversized.h	2020-08-07 11:06:11.667997389 -0700
+@@ -46,13 +46,13 @@
+    positive and N must be nonnegative.  This is a macro, not a
+    function, so that it works correctly even when SIZE_MAX < N.  */
+ 
+-#if 7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)
++#if ((7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)) && !defined __NVCOMPILER)
+ # define xalloc_oversized(n, s) \
+    __builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1)
+ #elif ((5 <= __GNUC__ \
+         || (__has_builtin (__builtin_mul_overflow) \
+             && __has_builtin (__builtin_constant_p))) \
+-       && !__STRICT_ANSI__)
++       && !__STRICT_ANSI__ && !defined __NVCOMPILER)
+ # define xalloc_oversized(n, s) \
+    (__builtin_constant_p (n) && __builtin_constant_p (s) \
+     ? __xalloc_oversized (n, s) \
+--- a/lib/intprops.h	2020-08-07 11:06:15.508012580 -0700
++++ b/lib/intprops.h	2020-08-07 11:07:54.379403731 -0700
+@@ -242,11 +242,11 @@
+ 
+ /* True if __builtin_add_overflow (A, B, P) works when P is non-null.  */
+ #define _GL_HAS_BUILTIN_OVERFLOW \
+-  (5 <= __GNUC__ || __has_builtin (__builtin_add_overflow))
++  ((5 <= __GNUC__ || __has_builtin (__builtin_add_overflow)) && !defined __NVCOMPILER)
+ 
+ /* True if __builtin_add_overflow_p (A, B, C) works.  */
+ #define _GL_HAS_BUILTIN_OVERFLOW_P \
+-  (7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p))
++  ((7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)) && !defined __NVCOMPILER)
+ 
+ /* The _GL*_OVERFLOW macros have the same restrictions as the
+    *_RANGE_OVERFLOW macros, except that they do not assume that operands
diff --git a/packages/m4/oneapi.patch b/packages/m4/oneapi.patch
new file mode 100644
index 0000000..d659c1e
--- /dev/null
+++ b/packages/m4/oneapi.patch
@@ -0,0 +1,18 @@
+--- a/lib/xalloc-oversized.h	2020-08-07 11:04:56.154698639 -0700
++++ b/lib/xalloc-oversized.h	2020-08-07 11:06:11.667997389 -0700
+@@ -46,13 +46,13 @@
+    positive and N must be nonnegative.  This is a macro, not a
+    function, so that it works correctly even when SIZE_MAX < N.  */
+ 
+-#if 7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)
++#if ((7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p)) && !defined __INTEL_LLVM_COMPILER)
+ # define xalloc_oversized(n, s) \
+    __builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1)
+ #elif ((5 <= __GNUC__ \
+         || (__has_builtin (__builtin_mul_overflow) \
+             && __has_builtin (__builtin_constant_p))) \
+-       && !__STRICT_ANSI__)
++       && !__STRICT_ANSI__ && !defined __INTEL_LLVM_COMPILER)
+ # define xalloc_oversized(n, s) \
+    (__builtin_constant_p (n) && __builtin_constant_p (s) \
+     ? __xalloc_oversized (n, s) \
diff --git a/packages/m4/package.py b/packages/m4/package.py
new file mode 100644
index 0000000..1dad2aa
--- /dev/null
+++ b/packages/m4/package.py
@@ -0,0 +1,127 @@
+# 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 os
+import re
+
+from spack.package import *
+
+
+class M4(AutotoolsPackage, GNUMirrorPackage):
+    """GNU M4 is an implementation of the traditional Unix macro processor."""
+
+    homepage = "https://www.gnu.org/software/m4/m4.html"
+    gnu_mirror_path = "m4/m4-1.4.18.tar.gz"
+
+    version("1.4.19", sha256="3be4a26d825ffdfda52a56fc43246456989a3630093cced3fbddf4771ee58a70")
+    version("1.4.18", sha256="ab2633921a5cd38e48797bf5521ad259bdc4b979078034a3b790d7fec5493fab")
+    version("1.4.17", sha256="3ce725133ee552b8b4baca7837fb772940b25e81b2a9dc92537aeaf733538c9e")
+
+    patch("gnulib-pgi.patch", when="@1.4.18")
+    patch("pgi.patch", when="@1.4.17")
+    # The NVIDIA compilers do not currently support some GNU builtins.
+    # Detect this case and use the fallback path.
+    patch("nvhpc.patch", when="@1.4.18 %nvhpc")
+    patch("nvhpc-1.4.19.patch", when="@1.4.19 %nvhpc")
+    # Workaround bug where __LONG_WIDTH__ is not defined
+    patch("nvhpc-long-width.patch", when="@1.4.19 %nvhpc")
+    patch("oneapi.patch", when="@1.4.18 %oneapi")
+    # from: https://github.com/Homebrew/homebrew-core/blob/master/Formula/m4.rb
+    # Patch credit to Jeremy Huddleston Sequoia <jeremyhu@apple.com>
+    patch("secure_snprintf.patch", when="@:1.4.18 os=highsierra")
+    patch("secure_snprintf.patch", when="@:1.4.18 os=mojave")
+    patch("secure_snprintf.patch", when="@:1.4.18 os=catalina")
+    patch("secure_snprintf.patch", when="@:1.4.18 os=bigsur")
+    # https://bugzilla.redhat.com/show_bug.cgi?id=1573342
+    patch(
+        "https://src.fedoraproject.org/rpms/m4/raw/5d147168d4b93f38a4833f5dd1d650ad88af5a8a/f/m4-1.4.18-glibc-change-work-around.patch",
+        sha256="fc9b61654a3ba1a8d6cd78ce087e7c96366c290bc8d2c299f09828d793b853c8",
+        when="@1.4.18",
+    )
+    # from: https://www.mail-archive.com/m4-patches@gnu.org/msg01208.html
+    # tests: Fix failing test checks/198.sysval with upstream patch for doc/m4.texi
+    patch("checks-198.sysval.1.patch", when="@1.4.19")
+    patch("checks-198.sysval.2.patch", when="@1.4.19")
+
+    variant("sigsegv", default=True, description="Build the libsigsegv dependency")
+
+    depends_on("diffutils", type="build")
+    depends_on("libsigsegv", when="+sigsegv")
+
+    build_directory = "spack-build"
+
+    tags = ["build-tools"]
+
+    executables = ["^g?m4$"]
+
+    @when("@1.4.19")
+    def patch(self):
+        """skip texinfo of m4.info for patched m4.texi (patched only a test in it)"""
+        timestamp = os.path.getmtime("doc/m4.info")
+        os.utime("doc/m4.texi", (timestamp, timestamp))
+
+    @classmethod
+    def determine_version(cls, exe):
+        # Output on macOS:
+        #   GNU M4 1.4.6
+        # Output on Linux:
+        #   m4 (GNU M4) 1.4.18
+        output = Executable(exe)("--version", output=str, error=str)
+        match = re.search(r"GNU M4\)?\s+(\S+)", output)
+        return match.group(1) if match else None
+
+    def setup_dependent_build_environment(self, env, dependent_spec):
+        # Inform autom4te if it wasn't built correctly (some external
+        # installations such as homebrew). See
+        # https://www.gnu.org/software/autoconf/manual/autoconf-2.67/html_node/autom4te-Invocation.html
+        env.set("M4", self.prefix.bin.m4)
+
+    def setup_run_environment(self, env):
+        env.set("M4", self.prefix.bin.m4)
+
+    def configure_args(self):
+        spec = self.spec
+        args = ["--enable-c++"]
+
+        if spec.satisfies("%cce@9:"):
+            args.append("LDFLAGS=-rtlib=compiler-rt")
+
+        if (
+            spec.satisfies("%clang")
+            or spec.satisfies("%aocc")
+            or spec.satisfies("%arm")
+            or spec.satisfies("%fj")
+        ) and not spec.satisfies("platform=darwin"):
+            args.append("LDFLAGS=-rtlib=compiler-rt")
+
+        if spec.satisfies("%intel@:18"):
+            args.append("CFLAGS=-no-gcc")
+
+        if "+sigsegv" in spec:
+            args.append("--with-libsigsegv-prefix={0}".format(spec["libsigsegv"].prefix))
+        else:
+            args.append("--without-libsigsegv-prefix")
+
+        # https://lists.gnu.org/archive/html/bug-m4/2016-09/msg00002.html
+        arch = spec.architecture
+        if arch.platform == "darwin" and arch.os == "sierra" and "%gcc" in spec:
+            args.append("ac_cv_type_struct_sched_param=yes")
+
+        return args
+
+    def test(self):
+        spec_vers = str(self.spec.version)
+        reason = "test: ensuring m4 version is {0}".format(spec_vers)
+        self.run_test(
+            "m4", "--version", spec_vers, installed=True, purpose=reason, skip_missing=False
+        )
+
+        reason = "test: ensuring m4 example succeeds"
+        test_data_dir = self.test_suite.current_test_data_dir
+        hello_file = test_data_dir.join("hello.m4")
+        expected = get_escaped_text_output(test_data_dir.join("hello.out"))
+        self.run_test(
+            "m4", hello_file, expected, installed=True, purpose=reason, skip_missing=False
+        )
diff --git a/packages/m4/pgi.patch b/packages/m4/pgi.patch
new file mode 100644
index 0000000..1ad63e2
--- /dev/null
+++ b/packages/m4/pgi.patch
@@ -0,0 +1,10 @@
+--- a/lib/config.hin
++++ b/lib/config.hin
+@@ -1510,6 +1510,7 @@
+       ? defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__ \
+       : (199901L <= __STDC_VERSION__ \
+          && !defined __HP_cc \
++         && !defined __PGI \
+          && !(defined __SUNPRO_C && __STDC__))) \
+      && !defined _GL_EXTERN_INLINE_APPLE_BUG)
+ # define _GL_INLINE inline
diff --git a/packages/m4/secure_snprintf.patch b/packages/m4/secure_snprintf.patch
new file mode 100644
index 0000000..da3ae5b
--- /dev/null
+++ b/packages/m4/secure_snprintf.patch
@@ -0,0 +1,15 @@
+With format string strictness, High Sierra also enforces that %n isn't used
+in dynamic format strings, but we should just disable its use on darwin in
+general.
+
+--- a/lib/vasnprintf.c.orig	2017-06-22 15:19:15.000000000 -0700
++++ b/lib/vasnprintf.c	2017-06-22 15:20:20.000000000 -0700
+@@ -4869,7 +4869,7 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *
+ #endif
+                   *fbp = dp->conversion;
+ #if USE_SNPRINTF
+-# if !(((__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) && !defined __UCLIBC__) || ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__))
++# if !defined(__APPLE__) && !(((__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) && !defined __UCLIBC__) || ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__))
+                 fbp[1] = '%';
+                 fbp[2] = 'n';
+                 fbp[3] = '\0';
diff --git a/packages/m4/test/hello.m4 b/packages/m4/test/hello.m4
new file mode 100644
index 0000000..6132c41
--- /dev/null
+++ b/packages/m4/test/hello.m4
@@ -0,0 +1,4 @@
+define(NAME, World)
+dnl This line should not show up
+// macro is ifdef(`NAME', , not)defined
+Hello, NAME!
diff --git a/packages/m4/test/hello.out b/packages/m4/test/hello.out
new file mode 100644
index 0000000..c8d3be7
--- /dev/null
+++ b/packages/m4/test/hello.out
@@ -0,0 +1,3 @@
+
+// macro is defined
+Hello, World!