Find xpidl.exe in Gecko SDK for compiling IDL files

If you are writing a new XPCOM component and need to use xpidl.exe to compile your IDL files, you can find xpidl.exe in the Gecko SDK, the latest version of which is here:

ftp://ftp.mozilla.org/pub/mozilla.org/mozilla/releases/mozilla1.7.3/

Yes, you can alternatively download the whole freaking mozilla codebase just to build xpidl.exe.

But hold on, it's not done yet. xpidl.exe probably complains that it can't find libIDL-0.6.dll in the path. You need to download the Netscape build tools,

http://ftp.mozilla.org/pub/mozilla.org/mozilla/source/wintools.zip

unzip them into some temporary folder, say C:\buildtools, and include C:\buildtools\windows\bin\x86 in your path.

And then xpidl.exe will whine some more, e.g., it can't read nsISupports.idl and nsrootidl.idl. Just copy those files from gecko-sdk\idl over to your current directory and try to compile again.

By the way, this is how I was told to run xpidl.exe:

xpidl.exe -m typelib -w -v -I $XPIDL_INC -o nsIMyInterface nsIMyInterface.idl

Setting XPIDL_INC to include gecko-sdk\idl doesn't seem to help.

Isn't Open Source wonderful? All the information you need is out there, all for free. You just need to spend 20 hours to find them, and your life has just been reduced by 40 days due to frustration. By the end of those 20 hours, you can't even remember what you initially set out to do.