Fix problem causing internal error when -z max-page-size is used.

If the default starting address is less than the new ABI page size,
we end up misaligning the file header, causing an internal error.

2016-12-01  Cary Coutant  <ccoutant@gmail.com>

gold/
	PR gold/20834
	* target.h (Target::default_text_segment_address): Bump default
	start address up to ABI page size.

diff --git a/gold/target.h b/gold/target.h
index 8e801e1..51402c2 100644
--- a/gold/target.h
+++ b/gold/target.h
@@ -119,9 +119,19 @@ class Target
   { return this->pti_->dynamic_linker; }
 
   // Return the default address to use for the text segment.
+  // If a -z max-page-size argument has set the ABI page size
+  // to a value larger than the default starting address,
+  // bump the starting address up to the page size, to avoid
+  // misaligning the text segment in the file.
   uint64_t
   default_text_segment_address() const
-  { return this->pti_->default_text_segment_address; }
+  {
+    uint64_t addr = this->pti_->default_text_segment_address;
+    uint64_t pagesize = this->abi_pagesize();
+    if (addr < pagesize)
+      addr = pagesize;
+    return addr;
+  }
 
   // Return the ABI specified page size.
   uint64_t