MFH: r561081

• Fix script used to extract themes to fallback to /tmp when both TMPDIR and XDG_CACHE_HOME environment variables are not defined [1]
• Fix crash caused by null terminated list missing the terminating null element due to no allocating enough elements [2]

Reported by: Andrea Venturoli <ml@netfence.it> [1] [2]
Patch submitted by: Andrea Venturoli <ml@netfence.it> [2]