Fix: make GCC.cmake host compatible

GCC.cmake holds generic functionality like running the preprocessor
on a file, creating raw binary output and so on. Common parts of the
file were executing cross-compilation specific code which made the
file incompatible to compiling code targeting the host machine. This
change makes these cross-compilation specific part execute conditionally
and thus allows using generic functionality when targeting the host.

Change-Id: I962ea47868d876c02a3c5ff9e18af13ff0813429
Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
diff --git a/environments/linux-pc/default_toolchain_file.cmake b/environments/linux-pc/default_toolchain_file.cmake
index 3f15eb3..e23bb79 100644
--- a/environments/linux-pc/default_toolchain_file.cmake
+++ b/environments/linux-pc/default_toolchain_file.cmake
@@ -44,4 +44,5 @@
 string(APPEND CMAKE_CXX_FLAGS_RELEASE_INIT " -O2")
 string(APPEND CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT " -O2")
 
+include($ENV{TS_ROOT}/tools/cmake/compiler/GCC.cmake REQUIRED)
 include($ENV{TS_ROOT}/tools/cmake/compiler/config_iface.cmake REQUIRED)