Fixes for gtests on gPrecise.

Also make a similar reservation in heap.cc use PROT_NONE rather than
PROT_READ which should be more efficient.

Change-Id: I648ef5b1bf2906094e92253b30d0a5a7554d1af6
diff --git a/src/mem_map.cc b/src/mem_map.cc
index 800f274..a2ddf3c 100644
--- a/src/mem_map.cc
+++ b/src/mem_map.cc
@@ -42,7 +42,7 @@
   return os;
 }
 
-void CheckMapRequest(byte* addr, size_t byte_count) {
+static void CheckMapRequest(byte* addr, size_t byte_count) {
   if (addr == NULL) {
     return;
   }
@@ -69,7 +69,6 @@
 
 MemMap* MemMap::MapAnonymous(const char* name, byte* addr, size_t byte_count, int prot) {
   CHECK_NE(0U, byte_count);
-  CHECK_NE(0, prot);
   size_t page_aligned_byte_count = RoundUp(byte_count, kPageSize);
   CheckMapRequest(addr, page_aligned_byte_count);