- Deal with different environt-setting syntax on Windows vs. Unix

- Remove the BoostBook XSL/DTD dir arguments from the BoostBook module (they really aren't useful)
- Add XSLTPROC argument to BoostBook module


[SVN r18129]

tools/build

@@ -1 +1 @@
-Subproject commit 696f3b7fab812e47f8c916c726700e34765ad7cc
+Subproject commit cc2dd7ff2f4c7c0916eeb845733f5eae8b574320