Extends configuration docs

docs/configuration.md

@@ -2,22 +2,65 @@ Catch is designed to "just work" as much as possible. For most people the only c
 
 Nonetheless there are still some occasions where finer control is needed. For these occasions Catch exposes a small set of macros for configuring how it is built.
 
+#  main()/ implementation
+
+	CATCH_CONFIG_MAIN	// Designates this as implementation file and defines main()
+	CATCH_CONFIG_RUNNER	// Designates this as implementation file
+
+Although Catch is header only it still, internally, maintains a distinction between interface headers and headers that contain implementation. Only one source file in your test project should compile the implementation headers and this is controlled through the use of one of these macros - one of these identifiers should be defined before including Catch in *exactly one implementation file in your project*.
+
+#  Prefixing Catch macros
+
+	CATCH_CONFIG_PREFIX_ALL
+
+To keep test code clean and uncluttered Catch uses short macro names (e.g. ```TEST_CASE``` and ```REQUIRE```). Occasionally these may conflict with identifiers from platform headers or the system under test. In this case the above identifier can be defined. This will cause all the Catch user macros to be prefixed with ```CATCH_``` (e.g. ```CATCH_TEST_CASE``` and ```CATCH_REQUIRE```).
+
+
 #  Terminal colour
 
-Yes, I am English, so I will continue to spell "colour" with a 'u'.
-
-When sending output to the terminal, if it detects that it can, Catch will use colourised text. On Windows the Win32 API, ```SetConsoleTextAttribute```, is used. On POSIX systems ANSI colour escape codes are inserted into the stream.
-
-For finer control you can define one of the following identifiers (these are mutually exclusive - but that is not checked so may behave unexpectedly if you mix them):
-
 	CATCH_CONFIG_COLOUR_NONE	// completely disables all text colouring
 	CATCH_CONFIG_COLOUR_WINDOWS	// forces the Win32 console API to be used
 	CATCH_CONFIG_COLOUR_ANSI	// forces ANSI colour codes to be used
 
+Yes, I am English, so I will continue to spell "colour" with a 'u'.
+
+When sending output to the terminal, if it detects that it can, Catch will use colourised text. On Windows the Win32 API, ```SetConsoleTextAttribute```, is used. On POSIX systems ANSI colour escape codes are inserted into the stream.
+
+For finer control you can define one of the above identifiers (these are mutually exclusive - but that is not checked so may behave unexpectedly if you mix them):
+
 Note that when ANSI colour codes are used "unistd.h" must be includable - along with a definition of ```isatty()```
 
 Typically you should place the ```#define``` before #including "catch.hpp" in your main source file - but if you prefer you can define it for your whole project by whatever your IDE or build system provides for you to do so.
 
+#  Console width
+
+	CATCH_CONFIG_CONSOLE_WIDTH = x // where x is a number
+
+Catch formats output intended for the console to fit within a fixed number of characters. This is especially important as indentation is used extensively and uncontrolled line wraps break this.
+By default a console width of 80 is assumed but this can be controlled by defining the above identifier to be a different value.
+
+#  stdout
+
+	CATCH_CONFIG_NOSTDOUT
+
+Catch does not use ```std::cout``` and ```std::cerr``` directly but gets them from ```Catch::cout()``` and ```Catch::cerr()``` respectively. If the above identifier is defined these functions are left unimplemented and you must implement them yourself. Their signatures are:
+
+    std::ostream& cout();
+    std::ostream& cerr();
+
+This can be useful on certain platforms that do not provide ```std::cout``` and ```std::cerr```, such as certain embedded systems.
+
+# C++ conformance toggles
+
+	CATCH_CONFIG_CPP11_NULLPTR
+	CATCH_CONFIG_CPP11_NOEXCEPT
+	CATCH_CONFIG_SFINAE				// Basic, C++03, support for SFINAE
+	CATCH_CONFIG_VARIADIC_MACROS 	// Usually pre-C++11 compiler extensions are sufficient
+	CATCH_CONFIG_NO_VARIADIC_MACROS	// Suppress if Catch is too eager to enable it
+
+Catch has some basic compiler detection that will attempt to select the appropriate mix of these macros. However being incomplete - and often without access to the respective compilers - this detection tends to be conservative.
+So overriding control is given to the user. If a compiler supports a feature (and Catch does not already detect it) then one or more of these may be defined to enable it (or suppress it, in some cases). If you do do this please raise an issue, specifying your compiler version (ideally with an idea of how to detect it) and stating that it has such support.
+
 ---
 
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