I finally broke down and decided to install a "real" C/C++ compiler to my work laptop. I had an old version of Borland C++ (4.52) that I use to teach my students about embedded software development, but I would hardly say that compiler is enough to suit my modern needs.
I searched for "Microsoft C Compiler cl.exe Download", sorted through a million or so results, and found a link on MSDN for "Windows Server 2003 Platform SDK R2". Last time I downloaded the platform SDK, it was exactly what I wanted, and though that was several years ago, I figured that a package with the same name would be the same product. I was wrong. I tried to do the "web-install", but that didn't work. The small installer program would open, initialize for a few moments, and then die with the error "This program does not appear to be a valid Microsoft Windows Installer." It told me to verify the download and try again. So I did, I re-downloaded and tried to run the web installer three more times, all with the same error. So I switched strategy, and went for the "Full Download" install, which required downloading several hundred megabytes of CAB files, unpacking them to reveal another set of CAB files and then a setup program to install the software. After several minutes of install, I come to find out that this isn't what I wanted. The only C compiler in that package was the 64-bit variant. So, I deleted this package and started over.
Second time through, I found the right install: "Microsoft Visual C++ SDK Express Edition". So I download the installer, tried to run it and... Error. "Could not download .NET Framework 3.5. Please exit the installer and try again". In the installer, you have the option to install Microsoft's Silverlight SDK along with the Visual C++ SDK. I choose to not install the Silverlight SDK because I simply don't need or want it. The second time, I again de-selected this option, and again the install failed with the same message. Having my suspicions (and knowing enough to know that Microsoft likes to bundle software you don't want in with the software you do want) I decided to try the install again, this time choosing to install Silverlight as well. Surprise! it works this time, and the ".NET Framework 3.5" was able to download sucessfully now that the system knows i'm also installing silverlight.
This whole process has taken up just over an hour of my evening, and while that might not seem to be too much time, it's still just another annoying interaction with Microsoft.