This allows you to load libstrangle without setting LD_LIBRARY_PATH to include
it. Only ENABLE_VK_LAYER_TORKEL104_libstrangle=1 is required now, as expected of
an implicit layer.
Previously, you were required to run your VK app via the wrapper:
STRANGLE_FPS=30 strangle vkcube
Now you can control it via simple environment variables alone:
ENABLE_VK_LAYER_TORKEL104_libstrangle=1 STRANGLE_FPS=30 vkcube
Naive concatenation of $LD_LIBRARY_PATH can result in an empty
colon-delimited segment; this tells glibc to load libraries from the
current directory, which is definitely wrong, and may be a security
vulnerability if the current directory is untrusted. (See #67234, for
example.) Fix this throughout the tree.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>