Shorten long shebangs only if the execute permission is set (#26899)

The OS should only interpret shebangs, if a file is executable. 

Thus, there should be no need to modify files where no execute bit is set. 

This solves issues that are e.g. encountered while packaging software as 
COVISE (https://github.com/hlrs-vis/covise), which includes example data
in Tecplot format. The sbang post-install hook is applied to every installed
file that starts with the two characters #!, but this fails on the binary Tecplot
files, as they happen to start with #!TDV. Decoding them with UTF-8 fails 
and an exception is thrown during post_install.

Co-authored-by: Martin Aumüller <aumuell@reserv.at>

0 files changed, 0 insertions, 0 deletions