Casting pid to ::pid_t when invoking syscall.

Summary:
syscalls involving pid/tid on 32 bit binaries are failing with
"Invalid argument" because the uint64_t arguments are too wide.

Reviewers: clayborg, ovyalov, sivachandra

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D7963

llvm-svn: 230817
diff --git a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
index b2754bc..4616163 100644
--- a/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
+++ b/lldb/source/Plugins/Process/Linux/ProcessMonitor.cpp
@@ -88,7 +88,8 @@
 
 // Try to define a macro to encapsulate the tgkill syscall
 // fall back on kill() if tgkill isn't available
-#define tgkill(pid, tid, sig)  syscall(SYS_tgkill, pid, tid, sig)
+#define tgkill(pid, tid, sig) \
+    syscall(SYS_tgkill, static_cast<::pid_t>(pid), static_cast<::pid_t>(tid), sig)
 
 using namespace lldb_private;