Support ANSI escape code on Windows

In some cases (e.g. when a build system pipes stderr) the Windows console
API cannot be used to color output. For these, provide a way to switch to
ANSI escape codes. This is required for Clang's -fansi-escape-codes option.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190460 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Process.cpp b/lib/Support/Process.cpp
index 2c0d37b..d5168f0 100644
--- a/lib/Support/Process.cpp
+++ b/lib/Support/Process.cpp
@@ -80,6 +80,24 @@
 #endif
 
 
+#define COLOR(FGBG, CODE, BOLD) "\033[0;" BOLD FGBG CODE "m"
+
+#define ALLCOLORS(FGBG,BOLD) {\
+    COLOR(FGBG, "0", BOLD),\
+    COLOR(FGBG, "1", BOLD),\
+    COLOR(FGBG, "2", BOLD),\
+    COLOR(FGBG, "3", BOLD),\
+    COLOR(FGBG, "4", BOLD),\
+    COLOR(FGBG, "5", BOLD),\
+    COLOR(FGBG, "6", BOLD),\
+    COLOR(FGBG, "7", BOLD)\
+  }
+
+static const char colorcodes[2][2][8][10] = {
+ { ALLCOLORS("3",""), ALLCOLORS("3","1;") },
+ { ALLCOLORS("4",""), ALLCOLORS("4","1;") }
+};
+
 // Include the platform-specific parts of this class.
 #ifdef LLVM_ON_UNIX
 #include "Unix/Process.inc"