Add gdb-6.8 support, courtesy Fathi Boudra

toolchain/gdb/6.8/600-fix-compile-flag-mismatch.patch

@@ -0,0 +1,31 @@
+--- a/gdb/gdbserver/configure
++++ b/gdb/gdbserver/configure
+@@ -1239,7 +1239,7 @@
+       ac_cache_corrupted=: ;;
+     ,);;
+     *)
+-      if test "x$ac_old_val" != "x$ac_new_val"; then
++      if test "`echo x$ac_old_val`" != "`echo x$ac_new_val`"; then
+ 	{ echo "$as_me:$LINENO: error: \`$ac_var' has changed since the previous run:" >&5
+ echo "$as_me: error: \`$ac_var' has changed since the previous run:" >&2;}
+ 	{ echo "$as_me:$LINENO:   former value:  $ac_old_val" >&5
+--- a/gdb/configure
++++ b/gdb/configure
+@@ -272,7 +272,7 @@
+ PACKAGE_BUGREPORT=
+ 
+ ac_unique_file="main.c"
+-ac_subdirs_all="$ac_subdirs_all doc testsuite"
++ac_subdirs_all="$ac_subdirs_all doc"
+ # Factoring default headers for most tests.
+ ac_includes_default="\
+ #include <stdio.h>
+@@ -3077,7 +3077,7 @@
+ 
+ 
+ 
+-subdirs="$subdirs doc testsuite"
++subdirs="$subdirs doc"
+ 
+ 
+ # Provide defaults for some variables set by the per-host and per-target