working patch

var/spack/repos/builtin/packages/m4/package.py

@@ -36,7 +36,7 @@ class M4(AutotoolsPackage):
 
     patch('gnulib-pgi.patch', when='@1.4.18')
     patch('pgi.patch', when='@1.4.17')
-    patch('sched_macos.patch', when='@1.4.17')
+    patch('sched_macos2.patch', when='@1.4.17')
 
     variant('sigsegv', default=True,
             description="Build the libsigsegv dependency")

var/spack/repos/builtin/packages/m4/sched_macos2.patch

+--- a/configure	2013-09-21 23:38:28.000000000 -0700
++++ b/configure	2016-09-23 13:23:48.591707322 -0700
+@@ -28724,7 +28724,7 @@
+
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ /* end confdefs.h.  */
+-
++       #include <errno.h>
+        #include <sched.h>
+        struct sched_param a;
+        int b[] = { SCHED_FIFO, SCHED_RR, SCHED_OTHER };
+@@ -28765,9 +28765,8 @@
+
+
+                cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+-/* end confdefs.h.  */
++#include <errno.h>
+ #include <sched.h>
+-
+ _ACEOF
+                                                                                                                         case "$host_os" in
+                  aix*) gl_absname_cpp="$ac_cpp -C" ;;
+@@ -28824,8 +28823,8 @@
+        HAVE_SCHED_H=0
+      fi
+
+-
+-     ac_fn_c_check_type "$LINENO" "struct sched_param" "ac_cv_type_struct_sched_param" "#include <sched.h>
++     ac_fn_c_check_type "$LINENO" "struct sched_param" "ac_cv_type_struct_sched_param" "#include <errno.h>
++#include <sched.h>
+ "
+ if test "x$ac_cv_type_struct_sched_param" = xyes; then :
+   HAVE_STRUCT_SCHED_PARAM=1