[m-rev.] for review: add csharp compiler output option

[Sebastian Godelet]

Hi,

Add --output-csharp-compiler option

In order to support more complicated linking scenarios linking .NET code 
with Mercury in the C# grade, add the --output-csharp-compiler option in 
the same way --output-c-compiler-type and --output-cc work.
This way makefiles can use something like:
CS_COMPILER := $(shell $(MMC) --output-csharp-compiler)

compiler/mercury_compile.m:
     Output the global csharp_compiler if the boolean option
     output_csharp_compiler is set.

compiler/options.m:
     Define the output_csharp_compiler option and provide the help text.

--

diff --git a/compiler/mercury_compile.m b/compiler/mercury_compile.m
index f60b5a6..035a325 100644
--- a/compiler/mercury_compile.m
+++ b/compiler/mercury_compile.m
@@ -372,6 +372,7 @@ main_after_setup(DetectedGradeFlags, 
OptionVariables, OptionArgs, Args,
      globals.lookup_bool_option(Globals, output_cc, OutputCC),
      globals.lookup_bool_option(Globals, output_c_compiler_type, 
OutputCCType),
      globals.lookup_bool_option(Globals, output_cflags, OutputCFlags),
+    globals.lookup_bool_option(Globals, output_csharp_compiler, OutputCSC),
      globals.lookup_bool_option(Globals, output_csharp_compiler_type,
          OutputCSCType),
      globals.lookup_bool_option(Globals, output_library_link_flags,
@@ -442,6 +443,10 @@ main_after_setup(DetectedGradeFlags, 
OptionVariables, OptionArgs, Args,
          io.stdout_stream(StdOut, !IO),
          output_c_compiler_flags(Globals, StdOut, !IO),
          io.nl(StdOut, !IO)
+    ; OutputCSC = yes ->
+        globals.lookup_string_option(Globals, csharp_compiler, CSC),
+        io.stdout_stream(StdOut, !IO),
+        io.write_string(StdOut, CSC ++ "\n", !IO)
      ; OutputCSCType = yes ->
          globals.lookup_string_option(Globals, csharp_compiler_type, 
CSC_Type),
          io.stdout_stream(StdOut, !IO),
diff --git a/compiler/options.m b/compiler/options.m
index f835979..6b661ec 100644
--- a/compiler/options.m
+++ b/compiler/options.m
@@ -209,6 +209,7 @@
      ;       output_libgrades
      ;       output_cc
      ;       output_c_compiler_type
+    ;       output_csharp_compiler
      ;       output_csharp_compiler_type
      ;       output_cflags
      ;       output_library_link_flags
@@ -1216,6 +1217,7 @@ option_defaults_2(output_option, [
      output_libgrades                    -   bool(no),
      output_cc                           -   bool(no),
      output_c_compiler_type              -   bool(no),
+    output_csharp_compiler              -   bool(no),
      output_csharp_compiler_type         -   bool(no),
      output_cflags                       -   bool(no),
      output_library_link_flags           -   bool(no),
@@ -2127,6 +2129,7 @@ long_option("output-libgrades", 
output_libgrades).
  long_option("output-cc",                output_cc).
  long_option("output-cc-type",           output_c_compiler_type).
  long_option("output-c-compiler-type",   output_c_compiler_type).
+long_option("output-csharp-compiler",   output_csharp_compiler).
  long_option("output-csharp-compiler-type", output_csharp_compiler_type).
  long_option("output-cflags",            output_cflags).
  long_option("output-library-link-flags",    output_library_link_flags).
@@ -3887,6 +3890,9 @@ options_help_output -->
          "--output-cflags",
          "\tPrint the flags with which the C compiler will be invoked",
          "\tto the standard output.",
+        "--output-csharp-compiler",
+        "\tPrint the command used to invoke the C# compiler to the",
+        "\tstandard output.",
          "--output-csharp-compiler-type",
          "\tPrint the C# compiler type to the standard output.",
          "--output-library-link-flags",