opencore-amr:

32-bit:
./configure --enable-static --disable-shared --disable-amrnb-encoder
make

64-bit:
./configure --host=x86_64-w64-mingw32 --enable-static --disable-shared --disable-amrnb-encoder
make

----------------------------------------------
Speex:

32-bit:
./configure --enable-sse --enable-static --disable-shared
make

64-bit:
./configure --host=x86_64-w64-mingw32 --enable-sse --enable-static --disable-shared