Merge pull request #2749 from jimklimov/Windows_cross_build_documenta…

…tion_cleaned

Windows cross build documentation cleaned

scripts/Windows/README.adoc

@@ -77,12 +77,33 @@ On Redhat and similar systems, use:
 You will also need pthread and mingw regex libraries, and other recommended
 dependencies as detailed below.
 
+[NOTE]
+======
+Be sure to install NUT build prerequisites and toolkits, as detailed
+in `docs/config-prereqs.txt` file.
+
+If builds complain similarly to
+----
+syntax error near unexpected token 'LIBUSB_1_0,'
+ 'PKG_CHECK_MODULES(LIBUSB_1_0, libusb-1.0 >= 0.9.1)'
+----
+make sure you have installed `pkgconf`, e.g.:
+
+	# apt-get install pkgconf
+======
+
 [NOTE]
 ================================================================================
 
 If you use script `./build-mingw-nut.sh` mentioned below, you may skip setting
-these environment variables when building NUT. You would however need to use
-them once (per `ARCH`) to provide the prerequisites below if built from source.
+these environment variables when building NUT itself. You would however need
+to use them once (per `ARCH`) to provide the prerequisites below if they are
+built from source.
+
+The build routines detailed below expect to be run in a terminal (shell per
+`ARCH`) with all these environment variables set once and inherited from one
+component build to another. Should you need to rebuild something, you would
+have to set these variables again in that session.
 
 When using the compilation approach, you would typically use the following
 `ARCH`, `HOST_FLAG` and `BUILD_FLAG`, as well as `CC`, `CFLAGS`, `LDFLAGS`
@@ -222,9 +243,12 @@ 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