[CMake] Clearing up custom targets/commands

[alaterale at elitemail.org]

Thanks everyone for your prompt responses to my questions.  I seem to
have a large supply of them, but I'm getting the hang of this more and
more I think :)

I have yet another question about how to do something in cmake.  How
would it be possible to add a bunch of conditionals to a custom target? 
I know you can make a custom target with ADD_CUSTOM_TARGET and add a
"command" with ADD_CUSTOM_COMMAND (which I'm guessing is a executable
command right?).  My confusing arises when trying to convert a part of
an ant build document that goes something like this:
<target name="init" depends="clean">
	<condition property="DEBUG" value="true">
		<not><isset property="${DEBUG}"/></not>
	</condition>
	<condition property="NOCRAWL" value="true">
		<not><isset property="${NOCRAWL}"/></not>
	</condition>
	<condition property="devflags" value="-DDEBUG=1">
		<istrue value="${DEBUG}"/>
	</condition>		
	<property name="cppflags" value="${devflags} ${phone_flag} -DLANG_${LANG}=1"/>
	<mkdir dir="${build}"/>
	<mkdir dir="${deploy}"/>
	<mkdir dir="${obf}"/>
</target>

Basically, I want to be able to only run the IFs if a certain make
target is called.  I don't really know how to do this with cmake, though
it has to be possible right?