sys_info_linux: positive return value of MaxSharedMemorySize for 32-bit build on 64-bit host.

base/sys_info_openbsd.cc

Index: base/sys_info_openbsd.cc
diff --git a/base/sys_info_openbsd.cc b/base/sys_info_openbsd.cc
index edbb2c9d86c305cdb605051d6165770e8ea3a28c..595291b0e018720d27a79cc629b5146008791d9e 100644
--- a/base/sys_info_openbsd.cc
+++ b/base/sys_info_openbsd.cc
@@ -49,7 +49,7 @@ int64 SysInfo::AmountOfAvailablePhysicalMemory() {
 }
 
 // static
-size_t SysInfo::MaxSharedMemorySize() {
+uint64 SysInfo::MaxSharedMemorySize() {
   int mib[] = { CTL_KERN, KERN_SHMINFO, KERN_SHMINFO_SHMMAX };
   size_t limit;
   size_t size = sizeof(limit);
@@ -57,7 +57,7 @@ size_t SysInfo::MaxSharedMemorySize() {
     NOTREACHED();
     return 0;
   }
-  return limit;
+  return static_cast<uint64>(limit);
 }
 
 // static