Make:Use environment variables for OS detection.

Add make helper files to select the appropriate settings for the build
environment. Selection is made in make_helpers/build_env.mk, which
selects other files to include using generic build environment settings.
The Trusted Firmware Makefile and supporting tool Makefiles are updated
to include build_env.mk instead of unix.mk.

NOTE: This change does not fully enable builds in other build
      environments. It facilitates this without compromising the
      existing build environments.

Change-Id: Ic4064ffe6ce158bbd16d7cc9f27dd4655a3580f6

1 files changed, 96 insertions, 0 deletions

diff --git a/make_helpers/build_env.mk b/make_helpers/build_env.mk
new file mode 100644
index 00000000..62c7f681
--- /dev/null
+++ b/make_helpers/build_env.mk
@@ -0,0 +1,96 @@
+#
+#  Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#
+#  Redistributions of source code must retain the above copyright notice, this
+#  list of conditions and the following disclaimer.
+#
+#  Redistributions in binary form must reproduce the above copyright notice,
+#  this list of conditions and the following disclaimer in the documentation
+#  and/or other materials provided with the distribution.
+#
+#  Neither the name of ARM nor the names of its contributors may be used
+#  to endorse or promote products derived from this software without specific
+#  prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+# This file contains the logic to identify and include any relevant
+# build environment specific make include files.
+
+ifndef BUILD_ENV_MK
+    BUILD_ENV_MK        :=      $(lastword $(MAKEFILE_LIST))
+
+    # Block possible built-in command definitions that are not fully portable.
+    # This traps occurences that need replacing with our OS portable macros
+    COPY                :=      $$(error "Replace COPY with call to SHELL_COPY or SHELL_COPY_TREE.")
+    CP                  :=      $$(error "Replace CP with call to SHELL_COPY or SHELL_COPY_TREE.")
+    DEL                 :=      $$(error "Replace DEL with call to SHELL_DELETE.")
+    MD                  :=      $$(error "Replace MD with call to MAKE_PREREQ_DIR.")
+    MKDIR               :=      $$(error "Replace MKDIR with call to MAKE_PREREQ_DIR.")
+    RD                  :=      $$(error "Replace RD with call to SHELL_REMOVE_DIR.")
+    RM                  :=      $$(error "Replace RM with call to SHELL_DELETE.")
+    RMDIR               :=      $$(error "Replace RMDIR with call to SHELL_REMOVE_DIR.")
+
+    ENV_FILE_TO_INCLUDE := unix.mk
+    ifdef OSTYPE
+        ifneq ($(findstring ${OSTYPE}, cygwin),)
+            ENV_FILE_TO_INCLUDE := cygwin.mk
+        else
+            ifneq ($(findstring ${OSTYPE}, MINGW32 mingw msys),)
+                ENV_FILE_TO_INCLUDE := msys.mk
+            endif
+        endif
+    else
+        ifdef MSYSTEM
+            # Although the MINGW MSYS shell sets OSTYPE as msys in its environment,
+            # it does not appear in the GNU make view of environment variables.
+            # We use MSYSTEM as an alternative, as that is seen by make
+            ifneq ($(findstring ${MSYSTEM}, MINGW32 mingw msys),)
+                OSTYPE ?= msys
+                ENV_FILE_TO_INCLUDE := msys.mk
+            endif
+        else
+            ifdef OS
+                ifneq ($(findstring ${OS}, Windows_NT),)
+                    ENV_FILE_TO_INCLUDE := windows.mk
+                endif
+            endif
+        endif
+    endif
+    include ${MAKE_HELPERS_DIRECTORY}${ENV_FILE_TO_INCLUDE}
+    ENV_FILE_TO_INCLUDE :=
+
+    ifndef SHELL_COPY
+        $(error "SHELL_COPY not defined for build environment.")
+    endif
+    ifndef SHELL_COPY_TREE
+        $(error "SHELL_COPY_TREE not defined for build environment.")
+    endif
+    ifndef SHELL_DELETE_ALL
+        $(error "SHELL_DELETE_ALL not defined for build environment.")
+    endif
+    ifndef SHELL_DELETE
+        $(error "SHELL_DELETE not defined for build environment.")
+    endif
+    ifndef MAKE_PREREQ_DIR
+        $(error "MAKE_PREREQ_DIR not defined for build environment.")
+    endif
+    ifndef SHELL_REMOVE_DIR
+        $(error "SHELL_REMOVE_DIR not defined for build environment.")
+    endif
+
+endif