[Bug 1877152] [NEW] I was painting a mask and it crush

Public bug reported: ``` GNU Image Manipulation Program version 2.10.14 git-describe: GIMP_2_10_12-511-ga4f55d6c7e C compiler: Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none

[Bug 1873749] [NEW] Gimp crashes

Public bug reported: ``` GNU Image Manipulation Program version 2.10.14 git-describe: GIMP_2_10_12-511-ga4f55d6c7e C compiler: Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none