+AS_CASE([$host_os],
+ [linux*], [OSTYPE="linux"],
+ [freebsd*], [OSTYPE="freebsd"],
+ [solaris*], [OSTYPE="solaris"],
+ [cygwin*], [OSTYPE="cygwin"],
+ [mingw*], [OSTYPE="mingw"],
+ [OSTYPE="unknown"]
+)
+AC_SUBST(OSTYPE)
+AM_CONDITIONAL([IS_LINUX], [test $OSTYPE = "linux"])
+
+
+
+# Userspace callstack capture is only supported by the Linux kernel on x86.