Build: AI-193.6911.18.40.6514223, 202005201507,

AI-193.6911.18.40.6514223, JRE 1.8.0_242-release-1644-b01x64 JetBrains s.r.o, OS Windows 10(amd64) v10.0 , screens 2160x1280

AS: 4.0; Kotlin plugin: 1.3.72-release-Studio4.0-1; Android Gradle Plugin: 4.0.0; Gradle: 6.5; NDK: from local.properties: 19.1.5304403, latest from SDK: 19.1.5304403; LLDB: LLDB 3.1 (revision: 3.1.4508709); CMake: from local.properties: (not specified), latest from SDK: 3.10.2, from PATH: (not found)

Android Gradle Plugin 4.0.0 (3.6.0+ may be affected too) ignore all cmake arguments which does not start with '-D' prefix. This break existing builds as '-C' is used to populate CMake cache with initial values.

From CMake help:
-C <initial-cache>           = Pre-load a script to populate the cache.

Repro:

pick any project with native code support via cmake
add extra arguments
examine top of cmake_server_log.txt file

Minimal example:

    // in build.gradle:
    externalNativeBuild {
        cmake {
            arguments '-CD:\\Test\\TargetProperties.cmake',
                      '-DCMAKE_BUILD_TYPE:STRING=Debug'
        }
    }

Android Gradle Plugin 4.0.0: all arguments not which does not start with '-D' are ignored

CMAKE SERVER: {
  "type": "configure",
  "cacheArguments": [
    ...
    "-DCMAKE_BUILD_TYPE:STRING\u003dDebug"
  ]
}

Android Gradle Plugin 3.5.3 correctly passes all arguments to CMake

CMAKE SERVER: {
  "type": "configure",
  "cacheArguments": [
    ...
    "-CD:\\Test\\TargetProperties.cmake",
    "-DCMAKE_BUILD_TYPE:STRING\u003dDebug"
  ]
}