Improve CMake build for Clang compiler

 Add -Wall and -Werror options for Clang compiler. The only reason for
 the -Werror option is because the build also enables it for other
 compilers. If it ever becomes an obstacle in future, it will be removed
 for all compilers. The important option is -Wall to detect code smells.

Author: leonlynch

CMakeLists.txt

@@ -37,6 +37,9 @@ if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
 	add_compile_options($<$<CONFIG:Debug>:-ggdb>)
 	add_compile_options($<$<CONFIG:RelWithDebInfo>:-ggdb>)
 endif()
+if(CMAKE_C_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+	add_compile_options(-Wall -Werror)
+endif()
 if(CMAKE_C_COMPILER_ID STREQUAL "AppleClang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
 	add_compile_options(-Wall -Werror)
 endif()