Use parallel make in godot-mono-builds scripts

Builds are faster with 64 jobs instead of 1 :)

It's mostly relevant for 'make' but we also use the -j flag
for 'configure' as it can also trigger a build for external
dependencies (like llvm for upcoming iOS Mono builds).

files/mono-build-win32.sh

@@ -17,7 +17,7 @@ export PATH="$(pwd)/.bin/:$PATH"
 ./autogen.sh $@ --disable-boehm --with-mcs-docs=no HOST_PROFILE=win32
 echo '#define HAVE_STRUCT_SOCKADDR_IN6 1' >> config.h
 pushd mcs/jay
-make CC=gcc
+make -j CC=gcc
 popd
 
 for dir in external/roslyn-binaries/Microsoft.Net.Compilers/[0-9]*; do