Scintilla 3.7.6/4.0.0 deprecated `SCE_*STYLEBITS*` and moved it to
deprecated features that require a build-time flag to be available.
Thus, drop use of those (as they are now no-ops anyway) and bump the
ABI (so plugins depending on those don't build mistakenly load) and API
(so a developer can guard use of those if wanted) version accordingly.
* Update Scintilla to version 3.7.5
This now requires a C++11-capable compiler.
Closes#1308.
* Test using newer dist on Travis
Since Scintilla needs C++11
* Add debugging code for when configure fails
* Workaround a pkg-config-corsswrapper bug on Ubuntu 14.04
See https://bugs.launchpad.net/ubuntu/+source/mingw-w64/+bug/1327242
