Merge branch 'msys2' of https://github.com/sitsofe/fio into master

* 'msys2' of https://github.com/sitsofe/fio:
  travis: cleanup build script
  configure: cleanup lex/yacc tests
  memlock: avoid type confusion in format string
  Makefile: introduce FIO_CFLAGS
  appveyor: cleanup and add separate install script
  Makefile/ci: Don't pass CFLAGS when linking
  configure/Makefile: add option to generate pdb symbols
  configure: be explicit about "XP" Windows API version
  windows: fix DWORD format string complaints
  windows: fix wrong format strings
  net: coerce the result of htonl before printing
  configure: pass non-null pointer to (v)asprintf