What seems to be the problem here ?

    pi@raspberrypi:~/SoapySDRPlay2/build $ make
-- Build type not specified: defaulting to release.
-- LIBSDRPLAY_INCLUDE_DIRS - /usr/local/include
-- LIBSDRPLAY_LIBRARIES - 
-- Configuring done
You have changed variables that require your cache to be deleted.
Configure will be re-run and you may have to reset some variables.
The following variables have changed:
CMAKE_CXX_COMPILER= /usr/bin/g++

-- The CXX compiler identification is GNU 8.3.0
-- Check for working CXX compiler: /usr/bin/g++
-- Check for working CXX compiler: /usr/bin/g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Build type not specified: defaulting to release.
-- Found libsdrplay: /usr/local/include, /usr/local/lib/libmirsdrapi-rsp.so
-- LIBSDRPLAY_INCLUDE_DIRS - /usr/local/include
-- LIBSDRPLAY_LIBRARIES - /usr/local/lib/libmirsdrapi-rsp.so
-- Performing Test HAS_STD_CXX11
-- Performing Test HAS_STD_CXX11 - Success
-- Configuring done
-- Generating done
-- Build files have been written to: /home/pi/SoapySDRPlay2/build
Scanning dependencies of target sdrPlaySupport
[  0%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Registration.cpp.o
[  0%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Settings.cpp.o
[  0%] Building CXX object CMakeFiles/sdrPlaySupport.dir/Streaming.cpp.o
make[2]: *** No rule to make target '/usr/local/lib/libmirsdrapi-rsp.so', needed by 'libsdrPlaySupport.so'.  Stop.
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/sdrPlaySupport.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
pi@raspberrypi:~/SoapySDRPlay2/build $ ls -l /usr/local/lib/libmirsdrapi-rsp.so
lrwxrwxrwx 1 root root 36 Jul 26 08:11 /usr/local/lib/libmirsdrapi-rsp.so -> /usr/local/lib/libmirsdrapi-rsp.so.2
pi@raspberrypi:~/SoapySDRPlay2/build $ vim  CMakeFiles/sdrPlaySupport.dir/link.txt 

CMakeLists.txt:

########################################################################
# Build Soapy SDR support module for SDRPlay
########################################################################
cmake_minimum_required(VERSION 2.8.7)
project(SoapySDRPlay CXX)

find_package(SoapySDR "0.4.0" NO_MODULE REQUIRED)
if (NOT SoapySDR_FOUND)
    message(FATAL_ERROR "Soapy SDR development files not found...")
endif ()

list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR})
find_package(LibSDRplay)

if (NOT LIBSDRPLAY_FOUND)
    message(FATAL_ERROR "SDRPlay development files not found...")
endif ()
message(STATUS "LIBSDRPLAY_INCLUDE_DIRS - ${LIBSDRPLAY_INCLUDE_DIRS}")
message(STATUS "LIBSDRPLAY_LIBRARIES - ${LIBSDRPLAY_LIBRARIES}")

include_directories(${CMAKE_CURRENT_SOURCE_DIR})
include_directories(${LIBSDRPLAY_INCLUDE_DIRS})

#enable c++11 features
if(CMAKE_COMPILER_IS_GNUCXX)

    #C++11 is a required language feature for this project
    include(CheckCXXCompilerFlag)
    CHECK_CXX_COMPILER_FLAG("-std=c++11" HAS_STD_CXX11)
    if(HAS_STD_CXX11)
        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
    else(HAS_STD_CXX11)
        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
    endif()

    #disable warnings for unused parameters
    add_definitions(-Wno-unused-parameter)

endif(CMAKE_COMPILER_IS_GNUCXX)

# Configurable feature set 
SET (RF_GAIN_IN_MENU ON CACHE BOOL "Add Rf gain as a setting, additionally to the IFGR gain control")

IF(RF_GAIN_IN_MENU) 
    ADD_DEFINITIONS( -DRF_GAIN_IN_MENU=1 )
ENDIF()

SOAPY_SDR_MODULE_UTIL(
    TARGET sdrPlaySupport
    SOURCES
        SoapySDRPlay.hpp
        Registration.cpp
        Settings.cpp
        Streaming.cpp
    LIBRARIES
        ${LIBSDRPLAY_LIBRARIES}
)