When we set LD_LIBRARY_PATH when building our host tools, we append any
pre-existing value to our custom path:
LD_LIBRARY_PATH="$(HOST_DIR)/usr/lib:$(LD_LIBRARY_PATH)"
But then if LD_LIBRARY_PATH was previously empty, we end up with an
LD_LIBRARY_PATH that ends with a colon.
Also, when we check that an existing LD_LIBRARY_PATH does not contain
CWD, we previously did not look for a zero-length prefix.
Since 'man ld.so' says of LD_LIBRARY_PATH:
A colon-separated list of directories in which to search for ELF
libraries at execution-time. Similar to the PATH environment
variable.
And POSIX states about PATH:
A zero-length prefix is a legacy feature that indicates the current
working directory.
And bash also recognises a zero-length prefix to search in CWD:
A zero-length (null) directory name in the value of PATH indicates
the current directory.
We may thus end up on a system where a zero-length prefix in
LD_LIBRARY_PATH is interpreted as CWD.
Do not append the previous LD_LIBRARY_PATH if it was empty, and check
for a zero-length prefix when checking dependencies.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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