build: download llvm and libffi from the JFrog repo

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

@@ -70,7 +70,7 @@ class CompileCppToBitcode extends DefaultTask {
 
         project.exec {
             workingDir objDir
-            executable "$project.llvmInstallPath/bin/clang++"
+            executable "$project.llvmDir/bin/clang++"
             args '-std=c++11'
 
             args compilerArgs
@@ -82,7 +82,7 @@ class CompileCppToBitcode extends DefaultTask {
         }
 
         project.exec {
-            executable "$project.llvmInstallPath/bin/llvm-link"
+            executable "$project.llvmDir/bin/llvm-link"
             args project.fileTree(objDir).include('**/*.bc')
 
             args linkerArgs

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

@@ -141,10 +141,10 @@ class NamedNativeInteropConfig extends AbstractFileCollection implements Named {
                     new File(project.findProject(":Interop:Indexer").buildDir, "nativelibs"),
                     new File(project.findProject(":Interop:Runtime").buildDir, "nativelibs")
             ).asPath
-            systemProperties "llvmInstallPath" : project.llvmInstallPath
+            systemProperties "llvmInstallPath" : project.llvmDir
             environment "LIBCLANG_DISABLE_CRASH_RECOVERY": "1"
-            environment "DYLD_LIBRARY_PATH": "${project.llvmInstallPath}/lib"
-            environment "LD_LIBRARY_PATH": "${project.llvmInstallPath}/lib"
+            environment "DYLD_LIBRARY_PATH": "${project.llvmDir}/lib"
+            environment "LD_LIBRARY_PATH": "${project.llvmDir}/lib"
 
             outputs.dir generatedSrcDir
             outputs.dir nativeLibsDir