title: Error occurs in Ninja while building CMake
body: <p>An error occurs while I am building CMake.</p>
  
  <p>build.gradle  file:</p>
  
  <pre><code>apply plugin: 'com.android.application'   android {
  compileSdkVersion 29
  buildToolsVersion "29.0.3"
  
  defaultConfig {
      applicationId "com.example.ffmpeg"
      minSdkVersion 14
      targetSdkVersion 29
      versionCode 1
      versionName "1.0"
  
      testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
      externalNativeBuild {
          cmake {
              cppFlags "-frtti -fexceptions"
              abiFilters 'arm64-v8a'
          }
      }
  }
  
  buildTypes {
      release {
          minifyEnabled false
          proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
      }
  }
  externalNativeBuild {
      cmake {
          path file('CMakeLists.txt')
      }
  }}dependencies {
  implementation fileTree(dir: 'libs', include: ['*.jar'])
  
  implementation 'androidx.appcompat:appcompat:1.1.0'
  implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
  testImplementation 'junit:junit:4.13'
  androidTestImplementation 'androidx.test.ext:junit:1.1.1'
  androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'}
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/hAzeB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hAzeB.png" alt="enter image description here"></a></p>
  
  <p>ERROR
  <a href="https://i.stack.imgur.com/aqYnE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aqYnE.png" alt="enter image description here"></a></p>
  
  <p>MY project </p>
  
  <p><a href="https://i.stack.imgur.com/Lg8li.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Lg8li.png" alt="enter image description here"></a></p>
  
  <p>Project Structure</p>
  
  <p><a href="https://i.stack.imgur.com/eO6XW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/eO6XW.png" alt="enter image description here"></a></p>
  
  <p>How can I solve this error?</p>
  
  <pre><code>Build command failed.
  
  Error while executing process D:\install\sdk\cmake\3.10.2.4988404\bin\ninja.exe with arguments {-C D:\Android projects\ffmpeg\app\.cxx\cmake\debug\arm64-v8a native-lib}
  
  ninja: Entering directory `D:\Android projects\ffmpeg\app\.cxx\cmake\debug\arm64-v8a'
  
  ninja: error: FindFirstFileExA(/d:/install/sdk/ndk/21.0.6113669/arm64-v8a): The filename, directory name, or volume label syntax is incorrect.
  </code></pre>