[C++] Drop -fpermissive hack

Both x86_64 GNU/Linux and x86_64 mingw-w64 build cleanly with
--enable-targets=all.  Let's drop the -fpermissive hack, in order to
let the buildbot catch C++ build regressions for us.

gdb/ChangeLog:
2015-11-19  Pedro Alves  <palves@redhat.com>

	* build-with-cxx.m4 (GDB_AC_BUILD_WITH_CXX): Remove -fpermissive.
	* configure: Regenerate.

gdb/gdbserver/ChangeLog:
2015-11-19  Pedro Alves  <palves@redhat.com>

	* configure: Regenerate.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2015-11-19  Pedro Alves  <palves@redhat.com>
+
+	* build-with-cxx.m4 (GDB_AC_BUILD_WITH_CXX): Remove -fpermissive.
+	* configure: Regenerate.
+
 2015-11-19  Pedro Alves  <palves@redhat.com>
 
 	* breakpoint.c (software_watchpoint_add_no_memory_location)

gdb/build-with-cxx.m4

@@ -32,8 +32,7 @@ AC_DEFUN([GDB_AC_BUILD_WITH_CXX],
     [enable_build_with_cxx=no])
 
   if test "$enable_build_with_cxx" = "yes"; then
-    # We're using -fpermissive as shortcut for now.
-    COMPILER='$(CXX) -fpermissive'
+    COMPILER='$(CXX)'
    else
     COMPILER='$(CC)'
   fi

gdb/configure

@@ -5015,8 +5015,7 @@ fi
 
 
   if test "$enable_build_with_cxx" = "yes"; then
-    # We're using -fpermissive as shortcut for now.
-    COMPILER='$(CXX) -fpermissive'
+    COMPILER='$(CXX)'
    else
     COMPILER='$(CC)'
   fi

gdb/gdbserver/ChangeLog

@@ -1,3 +1,7 @@
+2015-11-19  Pedro Alves  <palves@redhat.com>
+
+	* configure: Regenerate.
+
 2015-11-19  Yao Qi  <yao.qi@linaro.org>
 
 	* linux-aarch64-low.c (emit_data_processing_reg): Change opcode

gdb/gdbserver/configure

@@ -4827,8 +4827,7 @@ fi
 
 
   if test "$enable_build_with_cxx" = "yes"; then
-    # We're using -fpermissive as shortcut for now.
-    COMPILER='$(CXX) -fpermissive'
+    COMPILER='$(CXX)'
    else
     COMPILER='$(CC)'
   fi