build: add target native SDK as downloadable dependency

also improve Gradle native toolchains configuration

Interop/Indexer/build.gradle

@@ -16,13 +16,6 @@ def javaHome = System.getProperty('java.home')
 def compilerArgsForJniIncludes = ["", "linux", "darwin"].collect { "-I$javaHome/../include/$it" } as String[]
 
 model {
-    //TODO: it's better to find some way share this configuration
-    toolChains {
-        clang(Clang) {
-            path "${llvmDir}/bin/clang"
-        }
-    }
-
     components {
         clangbridge(NativeLibrarySpec) {
             sources {

Interop/Runtime/build.gradle

@@ -15,13 +15,6 @@ def javaHome = System.getProperty('java.home')
 def compilerArgsForJniIncludes = ["", "linux", "darwin"].collect { "-I$javaHome/../include/$it" } as String[]
 
 model {
-    //TODO: it's better to find some way share this configuration
-    toolChains {
-        clang(Clang) {
-            path "${llvmDir}/bin/clang"
-        }
-    }
-
     components {
         callbacks(NativeLibrarySpec) {
             sources.c.source {

backend.native/tests/build.gradle

@@ -12,6 +12,7 @@ abstract class KonanTest extends DefaultTask {
     def runtimeProject = project.project(":runtime")
     def llvmLlc = llvmTool("llc")
     def llvmC = llvmTool("clang")
+    def llvmCAdditionalArgs = ["--sysroot=$project.sysrootDir"]
     def runtimeBc = new File("${runtimeProject.buildDir.canonicalPath}/runtime.bc")
     def mainC = 'main.c'
     String goldValue = null
@@ -88,6 +89,8 @@ class UnitKonanTest extends KonanTest {
         project.exec {
             commandLine "${llvmC}", "${testC}", "${runtimeS.absolutePath}", "${sourceS.absolutePath}", "${mainC}",
                     "-o", "${exe.absolutePath}"
+
+            args llvmCAdditionalArgs
         }
     }
 }
@@ -97,6 +100,8 @@ class RunKonanTest extends KonanTest {
         project.exec {
             commandLine "${llvmC}", "-DRUN_TEST", "${runtimeS.absolutePath}", "${sourceS.absolutePath}", "${mainC}",
                     "-o", "${exe.absolutePath}"
+
+            args llvmCAdditionalArgs
         }
     }
 }

build.gradle

@@ -11,16 +11,16 @@ allprojects {
         evaluationDependsOn(":dependencies")
     }
 
-    afterEvaluate {
-        if (plugins.hasPlugin('c')) {
-            model {
-                toolChains {
-                    clang(Clang) {
-                        path "$llvmDir/bin"
+    plugins.withType(NativeComponentPlugin) {
+        model {
+            toolChains {
+                clang(Clang) {
+                    path "$llvmDir/bin"
 
-                        // The system PATH should be appended automatically according to Gradle docs,
-                        // but this doesn't seem to happen
-                        path System.env.PATH.split(File.pathSeparator)
+                    eachPlatform { // TODO: will not work when cross-compiling
+                        [cCompiler, cppCompiler, linker].each {
+                            it.withArguments { it << "--sysroot=$sysrootDir" }
+                        }
                     }
                 }
             }

buildSrc/src/main/groovy/org/jetbrains/kotlin/CompileToBitcode.groovy

@@ -73,6 +73,8 @@ class CompileCppToBitcode extends DefaultTask {
             executable "$project.llvmDir/bin/clang++"
             args '-std=c++11'
 
+            args "--sysroot=$project.sysrootDir"
+
             args compilerArgs
 
             args "-I$headersDir"

buildSrc/src/main/groovy/org/jetbrains/kotlin/NativeInteropPlugin.groovy

@@ -174,6 +174,10 @@ class NamedNativeInteropConfig implements Named {
                     args "-linker:" + linker
                 }
 
+                String sysrootArg = "--sysroot=$project.sysrootDir"
+                compilerOpts += sysrootArg
+                linkerOpts   += sysrootArg
+
                 args compilerOpts.collect { "-copt:$it" }
                 args linkerOpts.collect { "-lopt:$it" }
 

dependencies/build.gradle

@@ -85,6 +85,10 @@ task llvm(type: TgzNativeDep) {
     baseName = "clang+llvm-3.8.0-$target"
 }
 
+task sysroot(type: TgzNativeDep) {
+    baseName = "target-sysroot-1-$target"
+}
+
 
 task update {
     dependsOn tasks.withType(NativeDep)