Updated waf to 1.9.10.

NEW IN WAF 1.9.10
-----------------
* Detect -pie and -rdynamic in parse_flags #1936
* Fix Fortran module naming case
* Improve Visual Studio 2017 compilers detection (no vswhere/tools yet) #1925
* Prevent unnecessary Vala rebuilds due to vapi file installation
* Process .vapi files as input source files
* Reflect the current build group in bld.current_group
* Obtain NO_LOCK_IN_TOP/RUN/OUT from os.environ too
* Xcode9 generator fixes and example update #1939 #1943

(wiz)