Remove Phobos 3 dub.sdl and replace it with the build_v3.d build script. (#9069)

* Remove Phobos 3 dub.sdl and replace it with the build_v3.d buid script.

* Add environment bang to the build script.

* Fix the Phobos v3 build script so that unit tests work on POSIX.

---------

Co-authored-by: Jonathan M Davis <[email protected]>

Author: LightBender

.gitignore

@@ -27,3 +27,10 @@ libphobos_*
 source/
 
 tools/ucd*
+
+# Build specific exclusions
+*.o
+*.a
+*.obj
+*.exe
+unittest

build_v3.d

@@ -0,0 +1,140 @@
+#!/usr/bin/env rdmd
+/**
+Phobos V3 Build Script
+
+Usage:
+  ./build_v3.d [debug,release,unittest]
+*/
+
+import std.conv;
+import std.datetime;
+import std.file;
+import std.path;
+import std.process;
+import std.stdio;
+import std.string;
+
+int main(string[] args)
+{
+    int result = 0;
+
+    bool buildUnittest = false;
+    bool buildRelease = false;
+    if (args.length > 1)
+    {
+        buildUnittest = args[1] == "unittest";
+        buildRelease = args[1] == "release";
+    }
+
+    string argFilePath = buildNormalizedPath(getcwd(), "phobosbuildargs.txt");
+    auto dFiles = dirEntries(buildNormalizedPath(getcwd(), "phobos"), "*.d", SpanMode.breadth);
+    auto argFile = File(argFilePath, "w");
+
+    version(Windows)
+    {
+        string unittestExecutable = buildNormalizedPath(getcwd(), "unittest.exe");
+    }
+    else
+    {
+        string unittestExecutable = buildNormalizedPath(getcwd(), "unittest");
+    }
+
+    scope(exit)
+    {
+        argFile.close();
+        remove(argFilePath);
+
+        if (exists(unittestExecutable)) remove(unittestExecutable);
+    }
+
+    result = runCommand("dmd --version", getcwd());
+    if (result != 0)
+    {
+        writeln("Compiler Failure.");
+        return result;
+    }
+
+    writeln("Source files:");
+    //Add source file list to args file.
+    foreach(dFile; dFiles)
+    {
+        if (dFile.isDir()) continue;
+        argFile.writeln(dFile.name);
+        writeln(dFile.name);
+    }
+
+    //Add appropriate DMD arguments to the args file.
+    argFile.writeln("-od=./lib");
+    if (buildUnittest)
+    {
+        argFile.writeln("-main");
+        argFile.writeln("-unittest");
+        argFile.writeln("-debug");
+
+        version(Windows)
+        {
+            argFile.writeln("-of=unittest.exe");
+        }
+        else
+        {
+            argFile.writeln("-of=unittest");
+        }
+    }
+    else if (buildRelease)
+    {
+        argFile.writeln("-release -O");
+        argFile.writeln("-lib");
+        argFile.writeln("-of=libphobos3");
+    }
+    else
+    {
+        argFile.writeln("-debug");
+        argFile.writeln("-lib");
+        argFile.writeln("-of=libphobos3-debug");
+    }
+
+    argFile.flush();
+    argFile.close();
+
+    //Run the build.
+    result = runCommand("dmd @\"" ~ argFilePath ~ "\"", getcwd());
+    if (result != 0)
+    {
+        writeln("Build failed.");
+        return result;
+    }
+    else
+    {
+        writeln("Build successful.");
+        writeln();
+    }
+
+    //Run unittests if built.
+    if (buildUnittest)
+    {
+        writeln("Running tests...");
+        result = runCommand(unittestExecutable, getcwd());
+
+        if (result != 0)
+        {
+            writeln("Tests failed.");
+            return result;
+        }
+        else
+        {
+            writeln("Tests successful.");
+        }
+    }
+
+    return result;
+}
+
+private int runCommand(string command, string workDir)
+{
+    auto pid = pipeShell(command, Redirect.all, null, Config.none, workDir);
+    int result = wait(pid.pid);
+    foreach (line; pid.stdout.byLine) writeln(line);
+    foreach (line; pid.stderr.byLine) writeln(line);
+    writeln();
+    return result;
+}