[3.1] more cleanup to EosioTester.cmake to use CMAKE_INSTALL_FULL_LIBDIR instead

[spoonincode]

Some parts of EosioTester.cmake were still incorrect. It is looking for libraries in @CMAKE_INSTALL_PREFIX@/lib64 and @CMAKE_INSTALL_PREFIX@/lib however for something like Ubuntu 20.04, libraries get installed to ${CMAKE_INSTALL_PREFIX}/x86_64-linux-gnu! Change this to look for libraries in ${CMAKE_INSTALL_FULL_LIBDIR} instead -- the same location libraries are install()ed to.

Then fix up libbuiltins & libff to be consistent and install to ${CMAKE_INSTALL_FULL_LIBDIR} too.

Needs eosnetworkfoundation/mandel-fc#43 & eosnetworkfoundation/libff#3

Indirect work on #642

[spoonincode]

this section above could use some 👀

[linh2931]

If EOSIO_ROOT is not defined, would it be likely EOS_ROOT_DIR not defined either? It is safer to check if EOS_ROOT_DIR is defined before use.

[spoonincode]

@EOS_ROOT_DIR@ is always defined because it's replaced as part of the file configuration -- the resulting file will always be one of two values depending of it's building the file for the in-tree-build case (former) vs the installed case (latter)

mandel/CMakeLists.txt

Lines 194 to 195 in d668e01

	set(EOS_ROOT_DIR "${CMAKE_BINARY_DIR}/lib")
	configure_file(${CMAKE_SOURCE_DIR}/CMakeModules/eosio-config.cmake.in ${CMAKE_BINARY_DIR}/lib/cmake/eosio/eosio-config.cmake @ONLY)

mandel/CMakeLists.txt

Lines 199 to 200 in d668e01

	set(EOS_ROOT_DIR "${CMAKE_INSTALL_FULL_LIBDIR}")
	configure_file(${CMAKE_SOURCE_DIR}/CMakeModules/eosio-config.cmake.in ${CMAKE_BINARY_DIR}/modules/eosio-config.cmake @ONLY)

So the intention seems to be if EOSIO_ROOT is not defined then a sensible default should be used.

In-tree build

Previously

• set(EOS_ROOT_DIR ${CMAKE_BINARY_DIR})
• (no EOSIO_ROOT meant) set(EOSIO_ROOT "@EOS_ROOT_DIR@")
• list(APPEND CMAKE_MODULE_PATH ${EOSIO_ROOT}/lib/cmake/eosio)
list(APPEND CMAKE_MODULE_PATH ${EOSIO_ROOT}/lib64/cmake/eosio)

This ultimately meant for something like a build in /home/moomoo/mandel/build it'd end up adding these two paths to the CMAKE_MODULE_PATH

• /home/moomoo/mandel/build/lib/cmake/eosio
• /home/moomoo/mandel/build/lib64/cmake/eosio

Now

• set(EOS_ROOT_DIR ${CMAKE_BINARY_DIR}/lib)
• (no EOSIO_ROOT means just) list(APPEND CMAKE_MODULE_PATH @EOS_ROOT_DIR@/cmake/eosio)

So this means only /home/moomoo/mandel/build/lib/cmake/eosio is added to the CMAKE_MODULE_PATH but afaict this is fine since you'll never get a lib64 in such an in-tree case.

Installed

Previously

• set(EOS_ROOT_DIR ${CMAKE_INSTALL_PREFIX})
• (no EOSIO_ROOT meant) set(EOSIO_ROOT "@EOS_ROOT_DIR@")
• list(APPEND CMAKE_MODULE_PATH ${EOSIO_ROOT}/lib/cmake/eosio)
list(APPEND CMAKE_MODULE_PATH ${EOSIO_ROOT}/lib64/cmake/eosio)

This ultimately meant for something like an install with -DCMAKE_INSTALL_PREFIX=/usr you'd end up adding these two paths to the CMAKE_MODULE_PATH

• /usr/lib/cmake/eosio
• /usr/lib64/cmake/eosio

But this is wrong! The files were installed to /usr/lib/x86_64-linux-gnu/cmake/eosio instead.

Now

• set(EOS_ROOT_DIR ${CMAKE_INSTALL_FULL_LIBDIR}) -- critically this matches where the actual files will be install()ed
• (no EOSIO_ROOT means just) list(APPEND CMAKE_MODULE_PATH @EOS_ROOT_DIR@/cmake/eosio)

This will only end up with ${CMAKE_INSTALL_FULL_LIBDIR}/cmake/eosio as the CMAKE_MODULE_PATH but that'll always match up the actual installed path: /usr/lib/x86_64-linux-gnu/cmake/eosio

EOSIO_ROOT?

EOSIO_ROOT is the wild card here... I'm guessing some documentation or previous user workflow manually sets that and expects it to work. So I've decided to just keep the old behavior as-is since I'm not really sure all the different scenarios for that. Only the "automatic"/"fall back" logic when EOSIO_ROOT is not specified is changed.