build: Update waf to version 1.8.8-dev (with custom patches)

https://github.com/cawka/waf/tree/8f714a523d3b8c66f2949aaa8db91d6f7be55e55

This patch also ensures that unused-local-typedef warning does not
generate errors.

Change-Id: Ib0b2ebb745824a42770c955871b77de2f3ac0f33
Refs: #2209, #2657
diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index 759fcc8..2cd9573 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -141,6 +141,7 @@
         flags['CXXFLAGS'] += ['-std=c++11',
                               '-Wno-error=unneeded-internal-declaration', # Bug #1588
                               '-Wno-error=deprecated-register',
+                              '-Wno-error=unused-local-typedef', # Bug #2657
                               ]
         if Utils.unversioned_sys_platform() == "darwin":
             flags['CXXFLAGS'] += ['-stdlib=libc++']