cmake forcing the compiler makes the buil fail - cmake

Question

I thought specifying -DCMAKE_CXX_COMPILER_FORCED=1 -DCMAKE_C_COMPILER_FORCED=1 for cmake would make my build faster, because it would skip compiler checks. Instead, it makes my build fail:
#16 470.8 -- Found Git: /usr/bin/git (found version "2.17.1")
#16 470.8 -- Content of the error:
#16 470.8 -- Version of this git repo: v0.0.1-2-g93b2a22
#16 470.9 -- The C compiler identification is GNU 5.5.0
#16 470.9 -- The CXX compiler identification is GNU 5.5.0
#16 470.9 -- GCC detected - Adding flags
#16 471.0 -- Looking for pthread.h
#16 471.0 -- Looking for pthread.h - found
#16 471.0 -- Looking for pthread_create
#16 471.1 -- Looking for pthread_create - not found
#16 471.1 -- Looking for pthread_create in pthreads
#16 471.1 -- Looking for pthread_create in pthreads - not found
#16 471.1 -- Looking for pthread_create in pthread
#16 471.2 -- Looking for pthread_create in pthread - found
#16 471.2 -- Found Threads: TRUE
#16 471.2 -- Found Protobuf: /usr/local/lib/libprotobuf.so;-lpthread (found version "3.5.0")
#16 471.2 CMake Error at /opt/cmake/share/cmake-3.12/Modules/FindBoost.cmake:2048 (message):
#16 471.2 Unable to find the requested Boost libraries.
#16 471.2
#16 471.2 Boost version: 1.65.1
#16 471.2
#16 471.2 Boost include path: /usr/include
#16 471.2
#16 471.2 Could not find the following Boost libraries:
#16 471.2
#16 471.2 boost_graph
#16 471.2
#16 471.2 No Boost libraries were found. You may need to set BOOST_LIBRARYDIR to the
#16 471.2 directory containing Boost libraries or BOOST_ROOT to the location of
#16 471.2 Boost.
#16 471.2 Call Stack (most recent call first):
#16 471.2 CMakeLists.txt:24 (find_package)
#16 471.2
#16 471.2
#16 471.3 -- Configuring incomplete, errors occurred!
libboost-graph-dev is installed, so it's unclear what is happening here - if I remove the options, then the build is working.
What is happening here?

Answer 1

From the docs:
The Boost Graph Library is a header-only library and does not need to
be built to be used.
Header only libraries need not to be specified in the find_package(Boost ...) call. Remove it and instead link either to the target Boost::boost in your target_link_libraries call
or add include_directories(${Boost_INCLUDE_DIRS}) to your CMakeLists.txt file.