[m-rev.] for review: Remove documentation for --cross-compiling option.

[Peter Wang]

Remove documentation for --cross-compiling option.

README.Linux:
README.MacOS:
README.MinGW-cross:
compiler/options.m:
	Remove or comment out references to the `--cross-compiling'
	option which has no effect now.

diff --git a/README.Linux b/README.Linux
index 12a08c4..209a9f4 100644
--- a/README.Linux
+++ b/README.Linux
@@ -19,18 +19,9 @@ To build a 32-bit Mercury compiler on 64-bit Linux, follow these steps:
 (2) Ensure that you have a working Mercury compiler in your PATH
     to bootstrap from.
 
-(3) If the Mercury compiler in step (2) is a 64-bit compiler then add
-    the following line to a file named Mmake.params at the top-level
-    of the source tree:
-
-        MCFLAGS=--cross-compiling
-
-    If you are bootstrapping from an existing 32-bit compiler you
-    should not need to do this.
-
-(4) Run aclocal -I m4; autoconf as normal.  Then invoke configure
+(3) Run aclocal -I m4; autoconf as normal.  Then invoke configure
     as follows:
 
         $ ./configure --host=i686-pc-linux-gnu --with-cc="gcc -m32"
 
-(5) Do mmake; mmake install as normal.
+(4) Do mmake; mmake install as normal.
diff --git a/README.MacOS b/README.MacOS
index c0c79b2..cbfd05b 100644
--- a/README.MacOS
+++ b/README.MacOS
@@ -53,21 +53,6 @@ By default, 32-bit versions of the executables and libraries are installed on
 x86-64 machines running Mac OS X 10.5.  To build and install 64-bit Mercury on
 such a system you must pass the "-m64" option to the C compiler.
 
-Note that if you are building Mercury from scratch using an existing installed
-Mercury compiler, i.e. you are not installing using the pre-generated C files in
-the source distribution, and you are using a 32-bit Mercury compiler to
-bootstrap a 64-bit installation (or vice versa) then you must compile with
---cross-compiling enabled.  Not enabling it will result in library installation
-aborting with an error message like the following:
-
-    Uncaught Mercury exception:
-    Software Error: pred_table.m: Unexpected: can't locate compare/3
-
-You can enable cross-compilation by putting the following line in a file named
-Mmake.params at the top-level of the source tree:
-
-    MCFLAGS = --cross-compiling
-
 Mercury cannot be compiled with llvm-gcc on Mac OS X.
 
 If, after installing Mercury, you encounter errors about missing .mih files,
diff --git a/README.MinGW-cross b/README.MinGW-cross
index 3334f69..5d4b5d5 100644
--- a/README.MinGW-cross
+++ b/README.MinGW-cross
@@ -65,15 +65,11 @@ directory, e.g.
 
 Now you can run the 'mmc' script from the cross-compiled installation:
 
-    % /usr/local/mercury-mingw/bin/mmc -m hello --cross-compiling
+    % /usr/local/mercury-mingw/bin/mmc -m hello
     Making Mercury/int3s/hello.int3
     Making Mercury/ints/hello.int
     Making Mercury/cs/hello.c
     Making Mercury/os/hello.o
     Making hello.exe
 
-You should definitely pass `--cross-compiling' if mercury_compile was
-compiled for 64-bit Linux.  You can add it to the Mercury.config file for the
-Windows Mercury installation so you don't forget.
-
 -----------------------------------------------------------------------------
diff --git a/compiler/options.m b/compiler/options.m
index f835979..495aa0c 100644
--- a/compiler/options.m
+++ b/compiler/options.m
@@ -5975,17 +5975,18 @@ options_help_misc -->
         % `Mercury.config' file.  The `--fullarch' option is a deprecated
         % synonym for this.
 
-        "--cross-compiling",
-        "\tDo not assume that the code being generated is for the",
-        "\tplatform the compiler is running on.",
+% This option has no effect now.
+%       "--cross-compiling",
+%       "\tDo not assume that the code being generated is for the",
+%       "\tplatform the compiler is running on.",
 
         % The `--local-module-id' option is used by `mmc --make'.
         % The `--analysis-file-cache-dir' option is used by `mmc --make'.
 
-%        "--ignore-parallel-conjunctions",
-%        "\tReplace parallel conjunctions with plain ones, this is useful",
-%        "\tfor benchmarking.  Note that it does not affect implicit",
-%        "\tparallelism",
+%       "--ignore-parallel-conjunctions",
+%       "\tReplace parallel conjunctions with plain ones, this is useful",
+%       "\tfor benchmarking.  Note that it does not affect implicit",
+%       "\tparallelism",
 
         "--control-granularity",
         "\tDon't try to generate more parallelism than the machine can",
-- 
2.1.2