point people at more detailed build docs if they're on Windows

It's a hard balance between "most people want to run configure --bootstrap" and
"here's a massive wall of text of every detail about building".  I think the
balance in this change is better than it was before -- most people on Windows
don't want to build their own binary.

Fixes #983.

1 files changed, 18 insertions, 2 deletions

diff --git a/HACKING.md b/HACKING.md
index 9c6830f..1ba520c 100644
--- a/HACKING.md
+++ b/HACKING.md
@@ -2,10 +2,26 @@
 
 `./configure.py` generates the `build.ninja` files used to build
 ninja.  It accepts various flags to adjust build parameters.
+Run './configure.py --help' for more configuration options.
 
 The primary build target of interest is `ninja`, but when hacking on
-Ninja your changes should be testable so it's more useful to build
-and run `ninja_test` when developing.
+Ninja your changes should be testable so it's more useful to build and
+run `ninja_test` when developing.
+
+### Bootstrapping
+
+Ninja is built using itself.  To bootstrap the first binary, run the
+configure script as `./configure.py --bootstrap`.  It This first
+compiles all non-test source files together, then re-builds Ninja
+using itself.  You should end up with a `ninja' binary (or
+`ninja.exe`) in the source root.
+
+#### Windows
+
+On Windows, you'll need to install Python to run `configure.py`, and
+run everything under a Visual Studio Tools Command Prompt (or after
+running `vcvarsall` in a normal command prompt).  See below if you
+want to use mingw or some other compiler instead using Visual Studio.
 
 ### Adjusting build flags