./configure --host=mingw32 still uses gcc compiler

Hello,
I need to cross-compile several applications for Windows using MinGW.
The compilation is running under Ubuntu Linux.

This works fine with for example RoadNav (http://
roadnav.sourceforge.net), the compiler i586-mingw32msvc-gcc and other
binaries are detected:
>./configure --host=i586-mingw32msvc --build=linux
>checking for a BSD-compatible install... /usr/bin/install -c
>checking whether build environment is sane... yes
>checking for a thread-safe mkdir -p... /bin/mkdir -p
>checking for gawk... no
>checking for mawk... mawk
>checking whether make sets $(MAKE)... yes
>checking for i586-mingw32msvc-strip... i586-mingw32msvc-strip
>checking for style of include used by make... GNU
>checking for i586-mingw32msvc-gcc... i586-mingw32msvc-gcc
>checking for C compiler default output file name... a.exe
>checking whether the C compiler works... yes
>checking whether we are cross compiling... yes
>checking for suffix of executables... .exe
>...

However, for most other applications that I tried, the host system
type is reported correctly as i586-pc-mingw32msvc, but then the
standard gcc is used:
>./configure --host=i586-mingw32msvc --build=linux
>loading cache ./config.cache
>checking host system type... i586-pc-mingw32msvc
>checking host specific optimization flag... no
>checking for gcc... (cached) gcc
>checking whether the C compiler (gcc ) works... yes
>checking whether the C compiler (gcc ) is a cross-compiler... no
>checking whether we are using GNU C... (cached) yes

How do I get theses applications configured for MinGW?
What does it depend on, whether the application can actually be
configured for MinGW or whether the host flag is ignored?

Thanks
B.W.

(If you can point me to a newsgroup specific to GNU autotools, please
do so).