I am attempting to replace a home-grown build system with boost.build. I have just a couple days of experience with boost.build, so I am very new. <br /><br />One of the features of the previous system was that it would auto-select the version of gcc to use on a machine by using the first version that showed up on a list. (Most of the build machines have mutliple versions of gcc installed.) So, the build system would have a list such as:<br /><br />gcc-4.3<br />gcc-4.1<br />gcc-3.4<br /><br />The build system would first attempt to use gcc-4.3, if it was not available on the machine, it would try 4.1, etc... I would like to get similar functionality from boost.build. My naive approach was to create a site-config.jam file with something along the lines of:<br /><br />using gcc : 4.3 : gcc-4.3 ;<br />using gcc : 4.2 : gcc-4.2 ;<br />using gcc : 4.1 : gcc-4.1 ;<br /><br />This seemed to result in the system trying to build the project 3 times, once for each gcc version. Also, the &#39;list&#39; of gcc versions needs to be specified on a per-project basis. I.e. for some projects, gcc-3.x is the &#39;best&#39; compiler, because gcc 4.x will not work.<br /><br />So in summary: Is there a way to specify something along the lines of:<br /><br />if gcc-4.3 exists, use it<br />else if gcc-4.2 exists, use it,<br />else if gcc-4.1 exists, use it, etc.....