Build form Source Error

[pmaine]

I am building from source on a Raspberry Pi 4B and I get the following error:
cmake ..
-- Checking for module 'libairspy'
-- No package 'libairspy' found
CMake Error at /usr/share/cmake-3.16/Modules/FindPkgConfig.cmake:493 (message):
A required package was not found
Call Stack (most recent call first):
/usr/share/cmake-3.16/Modules/FindPkgConfig.cmake:677 (_pkg_check_modules_internal)
airspy_source/CMakeLists.txt:28 (pkg_check_modules)

-- Configuring incomplete, errors occurred!
See also "/home/pi/source/SDRPlusPlus/build/CMakeFiles/CMakeOutput.log".

[shuyuan-liu]

-- No package 'libairspy' found

You don't have the Airspy library installed, which is required for Airspy R2 and Airspy Mini support. If you use an Airspy SDR device, run sudo apt install libairspy-dev to install the files needed; if you don't need Airspy support, change OPT_BUILD_AIRSPY_SOURCE to OFF in CMakeLists.txt and try compiling again.

[pmaine]

The above response answered my question but GitHub wont let me mark as answered...