Minimal Gradle example for withType(CppCompile)

bar.cpp

int main() { }

build.gradle

apply plugin: 'cpp'

model {
  components {
    foo(NativeExecutableSpec) {
      sources {
        cpp {
          source {
            srcDirs '.'
            include 'foo.cpp'
          }
        }
      }

      binaries {
        all {
          lib library: 'rt', linkage: 'shared'
        }
      }
    }

    bar(NativeExecutableSpec) {
      sources {
        cpp {
          source {
            srcDirs '.'
            include 'bar.cpp'
          }
        }
      }

      binaries {
        all {
          lib library: 'rt', linkage: 'shared'
        }
      }
    }
  }

  repositories {
    libs(PrebuiltLibraries) {
      rt {
        headers.srcDir "/hoge/pos"
        binaries.withType(SharedLibraryBinary) {
          sharedLibraryFile = file("/usr/lib64/librt.so")
        }
      }
    }
  }
}

tasks.withType(CppCompile) {
  compilerArgs = ['-pthread']
  includes '/foo/bar'
}

foo.cpp

int main() { }

https://discuss.gradle.org/t/c-globally-set-compilerargs/11134