feat(ffmpeg): Allow --enable-static in ffmpeg (termux#21776)

Current if we replace `--disable-static` with `--enable-static` in
then it fails with error:

    aarch64-linux-android-ar: not found

Fixing this error and the next one:

    make: aarch64-linux-android-ranlib: No such file or directory

So now one can just replace `--disable-static` with `--enable-static`
and it will also provide static libraries.

%ci:no-build

packages/ffmpeg/build.sh

@@ -57,6 +57,8 @@ termux_step_configure() {
 		--cc="$CC" \
 		--cxx="$CXX" \
 		--nm="$NM" \
+		--ar="$AR" \
+		--ranlib="llvm-ranlib" \
 		--pkg-config="$PKG_CONFIG" \
 		--strip="$STRIP" \
 		--cross-prefix="${TERMUX_HOST_PLATFORM}-" \