[tools] Modify building.py and gcc.py for work with Python 3.

tools/building.py

@@ -806,7 +806,7 @@ def EndBuilding(target, program = None):
 
     if not GetOption('help') and not GetOption('target'):
         if not os.path.exists(rtconfig.EXEC_PATH):
-            print ("Error: the toolchain path ("+rtconfig.EXEC_PATH+") is not exist, please check 'EXEC_PATH' in path or rtconfig.py.")
+            print ("Error: the toolchain path (" + rtconfig.EXEC_PATH + ") is not exist, please check 'EXEC_PATH' in path or rtconfig.py.")
             need_exit = True
 
     if need_exit:

tools/gcc.py

@@ -55,14 +55,14 @@ def GetNewLibVersion(rtconfig):
             for line in f:
                 if line.find('_NEWLIB_VERSION') != -1 and line.find('"') != -1:
                     version = re.search(r'\"([^"]+)\"', line).groups()[0]
-        f.close()
+            f.close()
     elif CheckHeader(rtconfig, 'newlib.h'): # get version from newlib.h
         f = open(os.path.join(root, 'include', 'newlib.h'), 'r')
         if f:
             for line in f:
                 if line.find('_NEWLIB_VERSION') != -1 and line.find('"') != -1:
                     version = re.search(r'\"([^"]+)\"', line).groups()[0]
-        f.close()
+            f.close()
     return version
 
 def GCCResult(rtconfig, str):
@@ -148,7 +148,6 @@ def GCCResult(rtconfig, str):
             result += '#define LIBC_POSIX_THREADS 1\n'
 
         os.remove('__tmp.c')
-    f.close()
     return result
 
 def GenerateGCCConfig(rtconfig):