Rebase to FSF GDB 7.3.50.20110722.

Improve gcc-4.6 stdarg false prologue end workaround (GDB PR 12435 + GCC PR 47471).

gdb-7.2.50-sparc-add-workaround-to-broken-debug-files.patch

@@ -1,6 +1,8 @@
---- gdb-7.2.50.20110328.orig/gdb/dwarf2read.c	2011-03-30 12:52:20.395450001 +0200
-+++ gdb-7.2.50.20110328/gdb/dwarf2read.c	2011-03-30 13:41:55.485450006 +0200
-@@ -66,12 +66,14 @@
+Index: gdb-7.3.50.20110722/gdb/dwarf2read.c
+===================================================================
+--- gdb-7.3.50.20110722.orig/gdb/dwarf2read.c	2011-07-22 19:37:15.000000000 +0200
++++ gdb-7.3.50.20110722/gdb/dwarf2read.c	2011-07-22 19:44:42.000000000 +0200
+@@ -67,12 +67,14 @@
  #ifdef HAVE_ZLIB_H
  #include <zlib.h>
  #endif
@@ -15,7 +17,7 @@
  
  typedef struct symbol *symbolp;
  DEF_VEC_P (symbolp);
-@@ -1563,6 +1565,7 @@
+@@ -1618,6 +1620,7 @@ dwarf2_read_section (struct objfile *obj
          }
      }
  
@@ -23,7 +25,7 @@
  #ifdef HAVE_MMAP
    if (pagesize == 0)
      pagesize = getpagesize ();
-@@ -1589,6 +1592,7 @@
+@@ -1641,6 +1644,7 @@ dwarf2_read_section (struct objfile *obj
  	}
      }
  #endif
@@ -31,15 +33,15 @@
  
    /* If we get here, we are a normal, not-compressed section.  */
    info->buffer = buf
-@@ -15439,6 +15443,7 @@
+@@ -15983,6 +15987,7 @@ munmap_section_buffer (struct dwarf2_sec
  {
-   if (info->was_mmapped)
+   if (info->map_addr != NULL)
      {
 +#ifndef __sparc__
  #ifdef HAVE_MMAP
-       intptr_t begin = (intptr_t) info->buffer;
-       intptr_t map_begin = begin & ~(pagesize - 1);
-@@ -15449,6 +15454,7 @@
+       int res;
+ 
+@@ -15992,6 +15997,7 @@ munmap_section_buffer (struct dwarf2_sec
        /* Without HAVE_MMAP, we should never be here to begin with.  */
        gdb_assert_not_reached ("no mmap support");
  #endif