Detect cache line size on Linux for PPC hosts.

src/base/cpu.h

Index: src/base/cpu.h
diff --git a/src/base/cpu.h b/src/base/cpu.h
index ca108fa2bf91137b878d4365c6c5822e8a49fc68..3778d272334ef532e53dc058e2b1c826283c493d 100644
--- a/src/base/cpu.h
+++ b/src/base/cpu.h
@@ -75,6 +75,9 @@ class CPU final {
 
   // General features
   bool has_fpu() const { return has_fpu_; }
+  int icache_line_size() const { return icache_line_size_; }
+  int dcache_line_size() const { return dcache_line_size_; }
+  static const int UNKNOWN_CACHE_LINE_SIZE = 0;
 
   // x86 features
   bool has_cmov() const { return has_cmov_; }
@@ -118,6 +121,8 @@ class CPU final {
   int architecture_;
   int variant_;
   int part_;
+  int icache_line_size_;
+  int dcache_line_size_;
   bool has_fpu_;
   bool has_cmov_;
   bool has_sahf_;