DEBUGINFO: initial C bindings to debug info llvm

- support DICompileUnit
- support DIFIle
- support DISubroutine
- support DIBasicType
- support DILocation
- added gradle build
- debug info bindings are involved in kotlin build
- added binding to DIGetSubprogramLinkName
- added binding to LLVMBuilderGetCurrentFunction
- added reset location
- simple demo added (buildable with gradle)
  produces folowing output:
    Following pseudo code in sources.
     0:123456789012345678901
     1: fun main():Int {
     2:   {foo()}()
     3:   return 0
     4: }
     5  fun foo() {}

    0:b-backend-dwarf:minamoto@unit-703(0)# ./demo
    ; ModuleID = 'test'
    source_filename = "test"

    define i32 @foo(i32) !dbg !3 {
    entry:
      ret i32 %0, !dbg !7
    }

    !llvm.dbg.cu = !{!0}

    !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "konanc", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
    !1 = !DIFile(filename: "1.kt", directory: "src")
    !2 = !{}
    !3 = distinct !DISubprogram(name: "foo", linkageName: "foo:link", scope: null, file: !1, line: 66, type: !4, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, variables: !2)
    !4 = !DISubroutineType(types: !5)
    !5 = !{!6}
    !6 = !DIBasicType(name: "int", size: 32, align: 4)
    !7 = !DILocation(line: 42, column: 15, scope: !3)
- demo sharing debug information between several bitcode artifacts
    0:b-backend-dwarf:minamoto@unit-703(0)# llvmDebugInfoC/build/exe/demogenerated/demogenerated
    ; ModuleID = 'test'
    source_filename = "test"

    define void @foo() !dbg !3 {
    entry:
      ret void, !dbg !5
    }

    define void @"main$caller$foo"() !dbg !6 {
    entry:
      call void @foo(), !dbg !7
      ret void
    }

    define void @main() !dbg !8 {
    entry:
      call void @"main$caller$foo"(), !dbg !9
      ret void, !dbg !10
    }

    !llvm.dbg.cu = !{!0}

    !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "konanc", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
    !1 = !DIFile(filename: "<stdin>", directory: "")
    !2 = !{}
    !3 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !1, line: 5, type: !4, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, variables: !2)
    !4 = !DISubroutineType(types: !2)
    !5 = !DILocation(line: 5, column: 14, scope: !3)
    !6 = distinct !DISubprogram(name: "main$caller$foo", linkageName: "main$caller$foo", scope: null, file: !1, line: 2, type: !4, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, variables: !2)
    !7 = !DILocation(line: 5, column: 2, scope: !6)
    !8 = distinct !DISubprogram(name: "main", linkageName: "main", scope: null, file: !1, line: 1, type: !4, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, variables: !2)
    !9 = !DILocation(line: 2, column: 12, scope: !8)
    !10 = !DILocation(line: 3, column: 4, scope: !8)
- local variables support
- demo for local variable suppor (TBD some out put here).
    ; ModuleID = 'test'
    source_filename = "test"

    define i32 @main() !dbg !3 {
    entry:
    %0 = alloca i32
    call void @llvm.dbg.declare(metadata i32* %0, metadata !5, metadata !7), !dbg !8
    store i32 42, i32* %0, !dbg !8
    %1 = load i32, i32* %0, !dbg !8
    ret i32 %1, !dbg !8
    }

    ; Function Attrs: nounwind readnone
    declare void @llvm.dbg.declare(metadata, metadata, metadata) #0

    attributes #0 = { nounwind readnone }

    !llvm.dbg.cu = !{!0}

    !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "konanc", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
    !1 = !DIFile(filename: "<stdin>", directory: "")
    !2 = !{}
    !3 = distinct !DISubprogram(name: "main", linkageName: "main", scope: null, file: !1, line: 1, type: !4, isLocal: false, isDefinition: true, isOptimized: false, unit: !0, variables: !2)
    !4 = !DISubroutineType(types: !2)
    !5 = !DILocalVariable(name: "a", scope: !3, file: !1, line: 2, type: !6)
    !6 = !DIBasicType(name: "int", size: 32, align: 4)
    !7 = !DIExpression()
    !8 = !DILocation(line: 2, column: 1, scope: !3)

backend.native/build.gradle

@@ -153,6 +153,15 @@ kotlinNativeInterop {
      linkerOpts llvmLinkerOpts()
    }
 
+   debugInfo {
+     dependsOn ":llvmDebugInfoC:debugInfoStaticLibrary"
+     defFile '../llvmDebugInfoC/debugInfo.def'
+     compilerOpts "-fPIC", "-I$llvmDir/include", "-I${project(':llvmDebugInfoC').projectDir}/src/main/include"
+     if (isLinux()) {
+       linker 'clang++'
+     }
+   }
+
    hash { // TODO: copy-pasted from ':common:compileHash'
      compilerOpts '-fPIC'
      linkerOpts '-fPIC'
@@ -184,6 +193,7 @@ dependencies {
    compilerCompile kotlinCompilerModule
    compilerCompile kotlinNativeInterop['llvm'].configuration
    compilerCompile kotlinNativeInterop['hash'].configuration
+   compilerCompile kotlinNativeInterop['debugInfo'].configuration
 
    cli_bcCompile "org.jetbrains.kotlin:kotlin-runtime:$kotlin_version"
    cli_bcCompile sourceSets.compiler.output
@@ -264,7 +274,8 @@ task jars(type: Jar) {
     from 'build/classes/cli_bc', 
          'build/classes/compiler', 
          'build/classes/hashInteropStubs', 
-         'build/classes/llvmInteropStubs'
+         'build/classes/llvmInteropStubs',
+         'build/classes/debugInfoInteropStubs'
 
     dependsOn 'build', ':runtime:hostRuntime', 'external_jars'
 }