For building FLVStreamer from sources use MinGW+MSYS
http://www.mingw.org/

Extract FLVStreamer sources (flvstreamer-1.8l.tar.gz), enter to the directory and call
$ make -f MakefileWIN32


Compiler/linker flags:
CFLAGS=-Wall -D_FILE_OFFSET_BITS=64

CXXFLAGS=-D_FILE_OFFSET_BITS=64

LDFLAGS=-D_FILE_OFFSET_BITS=64