Fix: address Arm compiler licensing issue.

Fix for issue T19: https://issues.trustedfirmware.org/T19

Change details:
CompilerArmClangCommon.cmake:
  - Removed warning issued by cmake about incorrect licensing settings.

tfm_sw_requirement.md
  - Fixed incorrect Keil specific environment variable settings.
  - Copied licensing related warning to multiple places to make it more
    visible.
  - Some small improvements to help readability.

Change-Id: I6656ad0e9d9d668b2d2b70b18c19783b7cac03bf
Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
diff --git a/cmake/Common/CompilerArmClangCommon.cmake b/cmake/Common/CompilerArmClangCommon.cmake
index 9b69f8a..53f143a 100644
--- a/cmake/Common/CompilerArmClangCommon.cmake
+++ b/cmake/Common/CompilerArmClangCommon.cmake
@@ -1,5 +1,5 @@
 #-------------------------------------------------------------------------------
-# Copyright (c) 2017-2018, Arm Limited. All rights reserved.
+# Copyright (c) 2017-2019, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -21,11 +21,6 @@
 		message(FATAL_ERROR "ARMClang version (ARMCLANG_VER=${ARMCLANG_VER}) does not match ${MY_VERSION}")
 	endif()
 
-	#Emit warning if needed environment variables are not set.
-	if(NOT DEFINED ENV{ARM_TOOL_VARIANT} OR NOT DEFINED ENV{ARM_PRODUCT_PATH})
-		message(WARNING "ARM_TOOL_VARIANT or ARM_PRODUCT_PATH environment variables are not set!")
-	endif()
-
 	if (NOT DEFINED ARM_CPU_ARCHITECTURE AND NOT DEFINED ARM_CPU_TYPE)
 		message(FATAL_ERROR "ARM_CPU_TYPE and ARM_CPU_ARCHITECTURE is not defined! Please include the CPU specific config file before this one.")
 	endif()
diff --git a/docs/user_guides/tfm_sw_requirement.md b/docs/user_guides/tfm_sw_requirement.md
index 9c03cb8..cebd663 100755
--- a/docs/user_guides/tfm_sw_requirement.md
+++ b/docs/user_guides/tfm_sw_requirement.md
@@ -1,37 +1,36 @@
 # TF-M Software requirements
-
-## To compile TF-M code
-At least one of the supported compiler toolchains have to be available in the
-build environment.
+To compile TF-M code, at least one of the supported compiler toolchains have to
+be available in the build environment.
 The currently supported compiler versions are:
-- ARM Compiler v6.7.1
-- ARM Compiler v6.9
-- ARM Compiler v6.10
-- ARM Compiler v6.11
+- Arm Compiler v6.7.1
+- Arm Compiler v6.9
+- Arm Compiler v6.10
+- Arm Compiler v6.11
 - GNU Arm compiler v6.3.1
 - GNU Arm compiler v7.3
 
-*Note* The ARM compilers above are provided via Keil uVision v5.24.1 or greater,
-DS-5 v5.27.1 or greater, and Development Studio 2018.0, or they can be
-downloaded as standalone packages from [here](https://developer.arm.com/products/software-development-tools/compilers/arm-compiler/downloads/version-6).
+**Notes:**
 
-*Note* The GNU Arm compiler can be downloaded from [here](https://developer.arm.com/open-source/gnu-toolchain/gnu-rm/downloads).
-On the page select *GNU Arm Embedded Toolchain: 6-2017-q1-update* or *GNU Arm
-Embedded Toolchain: 7-2018-q2-update*
+  - The Arm compilers above are provided via Keil uVision v5.24.1 or greater,
+    DS-5 v5.27.1 or greater, and Development Studio 2018.0, or they can be
+    downloaded as standalone packages from [here](https://developer.arm.com/products/software-development-tools/compilers/arm-compiler/downloads/version-6).
 
-*Note* In this version, you also need manually clone CMSIS_5 and mbedtls
-repositories at the same location where tfm repo is located.
+  - The GNU Arm compiler can be downloaded from [here](https://developer.arm.com/open-source/gnu-toolchain/gnu-rm/downloads).
+    On the page select *GNU Arm Embedded Toolchain: 6-2017-q1-update* or *GNU Arm
+    Embedded Toolchain: 7-2018-q2-update*
 
-*Note* ARM compiler specific environment variable may need updating based
-on specific products and licenses as explained in
-[product-and-toolkit-configuration](https://developer.arm.com/products/software-development-tools/license-management/resources/product-and-toolkit-configuration).
+  - In this version, you also need manually clone CMSIS_5 and mbedtls
+    repositories at the same location where tfm repo is located.
+
+  - Arm compiler specific environment variable may need updating based
+    on specific products and licenses as explained in
+    [product-and-toolkit-configuration](https://developer.arm.com/products/software-development-tools/license-management/resources/product-and-toolkit-configuration).
 
 
-### Linux
+## Linux
 - DS-5 v5.27.1.
 - Git tools v2.10.0
-- Cmake v3.7.0
-  https://cmake.org/download/
+- [CMake v3.7.0](https://cmake.org/files/v3.7/)
 - GNU Make v3.81
 - Python3, with the following libraries:
   - pycrypto
@@ -41,17 +40,21 @@
   - sudo apt-get install python3-crypto python3-pyasn1 python3-yaml python3-jinja2
 - SRecord v1.58 (for Musca test chip boards)
 
+### Setup a shell to enable compiler toolchain and CMake after installation.
 
-#### Setup a shell to enable compiler toolchain and cmake after installation.
+To import Arm Compiler v6.7.1 in your bash shell console:
 
-To import ARM Compiler v6.7.1 in your bash shell console:
+**Note:** Arm compiler specific environment variable may need updating based
+on specific products and licenses as explained in
+[product-and-toolkit-configuration](https://developer.arm.com/products/software-development-tools/license-management/resources/product-and-toolkit-configuration).
+
 ~~~
 export PATH=<DS-5_PATH>/sw/ARMCompiler6.7.1/bin:$PATH
 export ARM_TOOL_VARIANT="ult"
 export ARM_PRODUCT_PATH="<DS-5_PATH>/sw/mappings"
 export ARMLMD_LICENSE_FILE="<LICENSE_FILE_PATH>"
 ~~~
-To import cmake in your bash shell console:
+To import CMake in your bash shell console:
 ~~~
 export PATH=<CMAKE_PATH>/bin:$PATH
 ~~~
@@ -60,45 +63,55 @@
 export PATH=<GNU_ARM_PATH>/bin:$PATH
 ~~~
 
-### On Windows
+## Windows
 - uVision v5.24.1 or DS-5 v5.27.1 (DS-5 Ultimate Edition) which provides the
-  ARM Compiler v6.7.1 compiler or GNU Arm compiler v6.3.1.
+  Arm Compiler v6.7.1 compiler or GNU Arm compiler v6.3.1.
 - Git client latest version (https://git-scm.com/download/win)
-- Cmake v3.7.0 ( https://cmake.org/download/ )
-- Cygwin ( https://www.cygwin.com/ ). Tests done with version 2.877 (64 bits)
-- GNU make should be installed by selecting appropriate package during cygwin
+- [CMake v3.7.0](https://cmake.org/files/v3.7/)
+- [Cygwin]( https://www.cygwin.com/ ). Tests done with version 2.877 (64 bits)
+- GNU make should be installed by selecting appropriate package during Cygwin
   installation.
-- Python3(native Windows version), with the following libraries:
+- Python3 [(native Windows version)](https://www.python.org/downloads/), with the following libraries:
   - pycryptodome (pip3 install --user pycryptodome)
   - pyasn1 (pip3 install --user pyasn1)
   - pyyaml (pip3 install --user pyyaml)
   - jinja2 (pip3 install --user jinja2)
 - Python3 pip
-- SRecord v1.63 (for Musca test chip boards)
+- [SRecord v1.63](https://sourceforge.net/projects/srecord/) (for Musca-A1 test chip board)
 
-#### Setup Cygwin to enable a compiler toolchain and cmake after installation.
+### Setup Cygwin to enable a compiler toolchain and CMake after installation.
 
-If applicable, import ARM Compiler v6.7.1 in your shell console. To make this
+If applicable, import Arm Compiler v6.7.1 in your shell console. To make this
 change permanent, add the command line into ~/.bashrc
 
-**DS5**
-~~~
-export PATH="/cygdrive/c/<DS-5 path>/sw/ARMCompiler6.7.1/bin":$PATH
-export ARM_PRODUCT_PATH="C:/<DS-5 path>/sw/mappings"
-~~~
+**DS-5**
 
-**Keil**
-~~~
-export PATH="/cygdrive/c/<uVison path>/ARM/ARMCLANG/bin":$PATH
-export ARM_PRODUCT_PATH="C:/<uVison path>/ARM/sw/mappings"
-~~~
+**Notes:**
 
-**Shared settings**
+  - Arm compiler specific environment variable may need updating based
+    on specific products and licenses as explained in
+    [product-and-toolkit-configuration](https://developer.arm.com/products/software-development-tools/license-management/resources/product-and-toolkit-configuration).
+
+  - Arm licensing related environment variables must use Windows paths,
+    and not the Cygwin specific one relative to */cygrive*.
+
 ~~~
+export PATH="/cygdrive/c/<DS-5_PATH>/sw/ARMCompiler6.7.1/bin":$PATH
+export ARM_PRODUCT_PATH="c:/<DS-5_PATH>/sw/mappings"
 export ARM_TOOL_VARIANT="ult"
 export ARMLMD_LICENSE_FILE="<LICENSE_FILE_PATH>"
 ~~~
 
+**Keil MDK Arm**
+
+**Note:** Arm compiler specific environment variable may need updating based
+on specific products and licenses as explained in
+[product-and-toolkit-configuration](https://developer.arm.com/products/software-development-tools/license-management/resources/product-and-toolkit-configuration).
+
+~~~
+export PATH="/cygdrive/c/<uVision path>/ARM/ARMCLANG/bin":$PATH
+~~~
+
 If applicable, import GNU Arm compiler v6.3.1 in your shell console. To make
 this change permanent, add the command line into ~/.bashrc
 
@@ -107,9 +120,9 @@
 export PATH=<GNU_ARM_PATH>/bin:$PATH
 ~~~
 
-To import cmake in your bash shell console:
+To import CMake in your bash shell console:
 
-**cmake**
+**CMake**
 
 ~~~
 export PATH=/cygdrive/c/<CMAKE_PATH>/bin:$PATH
@@ -171,5 +184,5 @@
 ~~~
 
 --------------
-*Copyright (c) 2017-2019, Arm Limited. All rights reserved.*
 
+*Copyright (c) 2017-2019, Arm Limited. All rights reserved.*