#155 Rare SEGV (null pointer deref) possible in main()

[Gregory Duck]

The XGetWMHints() function is can return NULL under some conditions (see below). But there is no NULL-check before the return value is used, leading to a SEGV (null pointer deref):

• https://sourceforge.net/p/mcj/xfig/ci/565f52f02a81a7dce20a5a00d664b6c71735d97b/tree/src/main.c#l1171

For reference, the relevant libx11 source code for XGetWMHints():

• https://gitlab.freedesktop.org/xorg/lib/libx11/-/blob/844271305a28e87031562dfeb43defbea02960a2/src/GetHints.c#L106

[tkl]

Thank you, mended with commit [ec49cd].