build: disable ranlib on mingw

Using ranlib is not required but prevents using the libraries with
msvc.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Martin Storsjö <martin@martin.st>

configure

@@ -2707,6 +2707,7 @@ case $target_os in
         SHFLAGS='-shared -Wl,--output-def,$$(@:$(SLIBSUF)=.def) -Wl,--out-implib,$(SUBDIR)lib$(SLIBNAME:$(SLIBSUF)=.dll.a) -Wl,--enable-runtime-pseudo-reloc -Wl,--enable-auto-image-base'
         objformat="win32"
         dlltool="${cross_prefix}dlltool"
+        ranlib=:
         enable dos_paths
         check_cflags -fno-common
         check_cpp_condition _mingw.h "defined (__MINGW64_VERSION_MAJOR) || (__MINGW32_MAJOR_VERSION > 3) \