Build: use target properties to define the target

Use target specific build parameters rather than the global ones to
define the build target.  This will simplify building multiple variants
of the target.

Author: compnerd

Sources/Build/LLBuildManifestBuilder.swift

@@ -619,18 +619,18 @@ extension LLBuildManifestBuilder {
             name: cmdName,
             inputs: inputs + [Node.file(target.sourcesFileListPath)],
             outputs: cmdOutputs,
-            executable: self.buildParameters.toolchain.swiftCompilerPath,
+            executable: target.buildParameters.toolchain.swiftCompilerPath,
             moduleName: target.target.c99name,
             moduleAliases: target.target.moduleAliases,
             moduleOutputPath: target.moduleOutputPath,
-            importPath: self.buildParameters.buildPath,
+            importPath: target.buildParameters.buildPath,
             tempsPath: target.tempsPath,
             objects: try target.objects,
             otherArguments: try target.compileArguments(),
             sources: target.sources,
             fileList: target.sourcesFileListPath,
             isLibrary: isLibrary,
-            wholeModuleOptimization: self.buildParameters.configuration == .release,
+            wholeModuleOptimization: target.buildParameters.configuration == .release,
             outputFileMapPath: try target.writeOutputFileMap() // FIXME: Eliminate side effect.
         )
     }