Set ecx to 0 when calling cpuid.

base/cpu.cc

Index: base/cpu.cc
diff --git a/base/cpu.cc b/base/cpu.cc
index af9c23da1a1ee2ceee74e48b729935032338472a..25328167425d4c0a242e0bfccaa47845737e81f9 100644
--- a/base/cpu.cc
+++ b/base/cpu.cc
@@ -60,23 +60,22 @@ namespace {
 #if defined(__pic__) && defined(__i386__)
 
 void __cpuid(int cpu_info[4], int info_type) {
-  __asm__ volatile (
-    "mov %%ebx, %%edi\n"
-    "cpuid\n"
-    "xchg %%edi, %%ebx\n"
-    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
-    : "a"(info_type)
-  );
+  __asm__ volatile(
+      "mov %%ebx, %%edi\n"
+      "cpuid\n"
+      "xchg %%edi, %%ebx\n"
+      : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]),
+        "=d"(cpu_info[3])
+      : "a"(info_type), "c"(0));
 }
 
 #else
 
 void __cpuid(int cpu_info[4], int info_type) {
-  __asm__ volatile (
-    "cpuid\n"
-    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
-    : "a"(info_type)
-  );
+  __asm__ volatile("cpuid\n"
+                   : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
+                     "=d"(cpu_info[3])
+                   : "a"(info_type), "c"(0));
 }
 
 #endif