[CMake] Setting rpath via LDFLAGS environment variable

[Ray Satiro]

I am building libssh with cmake. I have two versions of OpenSSL on my 
system and need libssh to use the later version of OpenSSL, which is in 
/usr/local/ssl/lib. I need that rpath both before and after install, as 
libssh should always use that version of OpenSSL. To do that I've been 
passing LDFLAGS:

cmake -E env LDFLAGS="-Wl,-rpath=/usr/local/ssl/lib" cmake 
-DCMAKE_BUILD_TYPE=RelWithDebInfo -DUNIT_TESTING=ON 
-DCMAKE_INSTALL_PREFIX=/usr/local -DOPENSSL_ROOT_DIR=/usr/local/ssl 
-DCMAKE_BUILD_TYPE=Debug ..

That works fine, but on install cmake says:

-- Set runtime path of "/usr/local/lib/libssh.so.4.8.1" to ""

However the rpath actually is in the file:

objdump -x /usr/local/lib/libssh.so.4.8.1 | grep RPATH
 ?? RPATH?????????????????????????????? /usr/local/ssl/lib

Is the message from cmake a bug or if not then is there a better way to 
pass rpath from the command line?