add autoconf archive ax_count_cpus.m4 macro

m4/ax_count_cpus.m4

@@ -0,0 +1,57 @@
+# ===========================================================================
+#       http://www.gnu.org/software/autoconf-archive/ax_count_cpus.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_COUNT_CPUS
+#
+# DESCRIPTION
+#
+#   Attempt to count the number of processors present on the machine. If the
+#   detection fails, then a value of 1 is assumed.
+#
+#   The value is placed in the CPU_COUNT variable.
+#
+# LICENSE
+#
+#   Copyright (c) 2012 Brian Aker <[email protected]>
+#   Copyright (c) 2008 Michael Paul Bailey <[email protected]>
+#   Copyright (c) 2008 Christophe Tournayre <[email protected]>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 10
+
+  AC_DEFUN([AX_COUNT_CPUS],[
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_REQUIRE([AC_PROG_EGREP])
+      AC_MSG_CHECKING([the number of available CPUs])
+      CPU_COUNT="0"
+
+      AS_CASE([$host_os],[
+        *darwin*],[
+        AS_IF([test -x /usr/sbin/sysctl],[
+          sysctl_a=`/usr/sbin/sysctl -a 2>/dev/null| grep -c hw.cpu`
+          AS_IF([test sysctl_a],[
+            CPU_COUNT=`/usr/sbin/sysctl -n hw.ncpu`
+            ])
+          ])],[
+        *linux*],[
+        AS_IF([test "x$CPU_COUNT" = "x0" -a -e /proc/cpuinfo],[
+          AS_IF([test "x$CPU_COUNT" = "x0" -a -e /proc/cpuinfo],[
+            CPU_COUNT=`$EGREP -c '^processor' /proc/cpuinfo`
+            ])
+          ])
+        ])
+
+      AS_IF([test "x$CPU_COUNT" = "x0"],[
+        CPU_COUNT="1"
+        AC_MSG_RESULT( [unable to detect (assuming 1)] )
+        ],[
+        AC_MSG_RESULT( $CPU_COUNT )
+        ])
+      ])