[IPOL discuss] minor compilation issues in "Combined First and Second Order Total Variation Inpainting using Split Bregman"

[Enric Meinhardt-Llopis]

> Finally, in newer ubuntu systems libpng is not located in /usr/lib so we
> need to change the following
> LDFLAGS= -L/usr/lib/x86_64-linux-gnu -lpng -lfftw3 -lgomp -lm

I disagree strongly.  It is irrelevant where the libraries are
installed on a specific distribution.  If they are INSTALLED, this
means that they can be found by the compiler when requesting them (via
-lpng).  If the operating system does not install libraries where they
can be found, this is a bug in the operating system.  It can be easily
solved by adding the directory to the LIBRARY_PATH environment
variable.

export LIBRARY_PATH=$LIBRARY_PATH:/usr/lib/x86_64-linux-gnu

The makefile is correct as it is, and the custom path should not be
added.  If we want to solve a particular bug of a particular operating
system, we can still do it by putting the line above in a custom
script "ubuntu-fix-bug.sh", which is to be called  before running the
makefile, and it sets the relevant variables, or whatever is needed.