scripts/Windows/README.adoc: corrected instructions of pthread instal…

…lation

Signed-off-by: RikyPlaza <158032745+RikyPlaza@users.noreply.github.com>

scripts/Windows/README.adoc

@@ -226,9 +226,12 @@ presumed inconsequential. You can try a not-"inlined" build instead.
 
 Finally, install the resulting files into locations under `PREFIX`:
 
-	:; sudo cp *.dll ${PREFIX}/pthreads/lib/
-	:; sudo cp *.a ${PREFIX}/lib/
-	:; sudo cp pthread.h sched.h semaphore.h ${PREFIX}/pthreads/include
+	:; sudo mkdir -p $PREFIX/pthreads/lib/
+	:; sudo cp *.dll $PREFIX/pthreads/lib/
+	:; sudo mkdir -p $PREFIX/lib/
+	:; sudo cp *.a $PREFIX/lib/
+	:; sudo mkdir -p $PREFIX/pthreads/include/
+	:; sudo cp pthread.h sched.h semaphore.h $PREFIX/pthreads/include
 
 
 MinGW regex library