K-Meleon is based on MfcEmbed, which is a embedding test browser in Mozilla. MfcEmbed uses the MFC libraries which are in Microsoft Visual C++. Mozilla can be build with MinGW, but MfcEmbed and K-Meleon can't because of this.
Also, there is some problems in the MinGW builds of Mozilla, like some of the Mozilla/Netscape plugins wont work. The greatest is probably Suns Java plugin, which is used much.
MinGW is only a Tier-3 platform and MVC++ is a Tier-1 platform in Mozilla (
http://www.mozilla.org/build/faq.html#supported), which means MVC++ is Mozillas primary focus for Win32 platforms.
Getting K-Meleon to build with MinGW would mean a complete redo of the source code, 'cause MFC is Microsofts property and it surely won't let free compilers to use it.
This is one of the things I don't like about K-Meleon, but it isn't K-Meleons developers fault. Go blame to Mozilla for using MVC++ in the first place. The second thing I don't like about K-Meleon is that it isn't for Linux. :p And those are about the only things I don't like about K-Meleon, otherwise I love it. =)
-dpb