Move freebsd-g++ mkspecs back for supported FreeBSD 9.3 and up

FreeBSD 9.3 is still supported and uses gcc as the default
compiler, therefore FreeBSD ports require patching the mkspecs
back. To avoid patching, move the mkspecs back to the right
place and adapt the path in the qmake.conf/qplatformdefs.h

[ChangeLog][FreeBSD] The freebsd-g++ mkspec was moved back and no
longer requires the "unsupported/" prefix, matching the FreeBSD
ports tree, as FreeBSD 9.3 still defaults to using GCC. Users of
GCC that did not previously use the ports patch will need to adapt their
build scripts and drop the "unsupported/" prefix.

Change-Id: Ideda4a33cccf5381000f6f50b6ae92a5c24ba9d4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

configure

@@ -2872,7 +2872,7 @@ if [ -z "$PLATFORM" ]; then
      FreeBSD:*)
         PLATFORM=freebsd-clang
         PLATFORM_NOTES="
-            - Also available for FreeBSD: freebsd-icc
+            - Also available for FreeBSD: freebsd-g++
         "
         ;;
      OpenBSD:*)

mkspecs/freebsd-g++/qmake.conf

@@ -5,7 +5,7 @@
 MAKEFILE_GENERATOR      = UNIX
 QMAKE_PLATFORM          = freebsd bsd
 
-include(../../common/unix.conf)
+include(../common/unix.conf)
 
 QMAKE_CFLAGS_THREAD     = -pthread -D_THREAD_SAFE
 
@@ -29,6 +29,6 @@ QMAKE_OBJCOPY           = objcopy
 QMAKE_NM                = nm -P
 QMAKE_RANLIB            =
 
-include(../../common/gcc-base-unix.conf)
-include(../../common/g++-unix.conf)
+include(../common/gcc-base-unix.conf)
+include(../common/g++-unix.conf)
 load(qt_config)

mkspecs/freebsd-g++/qplatformdefs.h

@@ -31,4 +31,4 @@
 **
 ****************************************************************************/
 
-#include "../../freebsd-clang/qplatformdefs.h"
+#include "../freebsd-clang/qplatformdefs.h"