docs: clarify build environment prerequisites

Our build system extensively uses syntax and tools that are not natively
supported by Windows shells (i.e., CMD.exe and Powershell). This
dependency necessitates a UNIX-compatible build environment. This commit
updates the prerequisites section in our documentation to reflect this.

Change-Id: Ia7e02d7a335e6c88bbaa0394650f1313cdfd6e40
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index 9053e34..8ad53a4 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -11,12 +11,11 @@
 Build Host
 ----------
 
-|TF-A| can be built using either a Linux or a Windows machine as the build host.
+|TF-A| can be compiled on both Linux and Windows-based machines.
+However, we strongly recommend using a UNIX-compatible build environment.
 
-A relatively recent Linux distribution is recommended for building |TF-A|. We
-have performed tests using Ubuntu 22.04 LTS (64-bit) but other distributions
-should also work fine as a base, provided that the necessary tools and libraries
-can be installed.
+Testing is performed using Ubuntu 22.04 LTS (64-bit), but other distributions
+should also work, provided the necessary tools and libraries are installed.
 
 .. _prerequisites_toolchain:
 
@@ -43,10 +42,6 @@
    reports are always welcome.
 
 .. note::
-   The software has also been built on Windows 7 Enterprise SP1, using CMD.EXE,
-   Cygwin, and Msys (MinGW) shells, using version 5.3.1 of the GNU toolchain.
-
-.. note::
    For instructions on how to select the cross compiler refer to
    :ref:`Performing an Initial Build`.