PTRACE_GETREGS might not be detected on some distro, due to a missing #include
in the configure test.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14899 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.ac b/configure.ac
index bdf5f22..fe2897b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1084,6 +1084,7 @@
 
 AC_MSG_CHECKING([for PTRACE_GETREGS])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <stdlib.h>
 #include <stddef.h>
 #include <sys/ptrace.h>
 #include <sys/user.h>