valgrind: add patch to fix build on PowerPC uClibc

uClibc on PowerPC forgot to define some PTRACE_* definitions. Even
though the Buildroot uClibc package has a fix for this, it doesn't fix
external uClibc toolchains that are not patched. Therefore this commit
adds a patch to Valgrind to workaround the problem by defining
PTRACE_GETSIGINFO to the appropriate value on PowerPC when it's not
defined by the C library.

Fixes:

  http://autobuild.buildroot.org/results/bc6/bc6be9aa1ad39201a1045a65c0c3eb1e968371f2/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/valgrind/valgrind-0003-add-missing-ptrace-getsiginfo-on-powerpc.patch

@@ -0,0 +1,28 @@
+Define PTRACE_GETSIGINFO on PowerPC when not available
+
+uClibc 0.9.33.2 does not define PTRACE_GETSIGINFO in PowerPC. Even
+though Buildroot has a uClibc patch doing that, it doesn't solve the
+case of external uClibc toolchain from other sources (such as
+Crosstool-NG). Therefore, this patch modifies Valgrind to define
+PTRACE_GETSIGINFO on PowerPC to the right value, when such definition
+is not available from the C library.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+
+Index: b/coregrind/vgdb-invoker-ptrace.c
+===================================================================
+--- a/coregrind/vgdb-invoker-ptrace.c
++++ b/coregrind/vgdb-invoker-ptrace.c
+@@ -71,6 +71,12 @@
+ #   endif
+ #endif
+ 
++#if defined(__powerpc__)
++# ifndef PTRACE_GETSIGINFO
++#  define PTRACE_GETSIGINFO 0x4202
++# endif
++#endif
++
+ #if VEX_HOST_WORDSIZE == 8
+ typedef Addr64 CORE_ADDR;
+ #elif VEX_HOST_WORDSIZE == 4