Fix: Eliminate warnings

Consider warnings as errors and correct them.

Signed-off-by: Gabor Toth <gabor.toth2@arm.com>
Change-Id: I2d777ee56b21750966b75147be6c4eb73229043f
diff --git a/environments/linux-pc/default_toolchain_file.cmake b/environments/linux-pc/default_toolchain_file.cmake
index e23bb79..58f29bc 100644
--- a/environments/linux-pc/default_toolchain_file.cmake
+++ b/environments/linux-pc/default_toolchain_file.cmake
@@ -11,7 +11,7 @@
 
 set(TS_DEBUG_INFO_FLAGS "-fdiagnostics-show-option -gdwarf-2" CACHE STRING "Compiler flags to add debug information.")
 set(TS_MANDATORY_AARCH_FLAGS "" CACHE STRING "Compiler flags configuring architecture specific ")
-set(TS_WARNING_FLAGS "-Wall" CACHE STRING "Compiler flags affecting generating warning messages.")
+set(TS_WARNING_FLAGS "-Wall -Werror" CACHE STRING "Compiler flags affecting generating warning messages.")
 set(TS_MANDATORY_LINKER_FLAGS "" CACHE STRING "Linker flags needed for correct builds.")
 
 # Set flags affecting all build types