Fix warning (use of uninitialized value) added per...

Fix warning (use of uninitialized value) added per d0a842c5 (fixes !54 (comment 137742985))
4 jobs for master in 4 minutes and 34 seconds
Status Job ID Name Coverage
  Build
passed #155299269
autoconf

00:04:34

passed #155299270
cmake-makefiles

00:02:53

passed #155299271
cmake-ninja

00:02:32

 
  External
passed continuous-integration/appveyor/branch