Add quotes for most arguments when building bjam. This solves the problem of externally specified values, like the Python path, from breaking when they have spaces.

[SVN r49887]

tools/build

@@ -1 +1 @@
-Subproject commit dd458ca471767f961de604315607d2b13c3c0061
+Subproject commit 4a7c8b96875bfd649ad46a66fab5fcf8c1fd95c6