Source/autotools/SetupCompilerFlags.m4

# Use C99 as the language standard for C code.
CFLAGS="$CFLAGS -pthread -std=c99"
# Use the C++11 standard. Do not warn about C++11 incompatibilities.
CXXFLAGS="$CXXFLAGS -pthread -std=c++11 -Wno-c++11-compat"

# Clang requires suppression of unused arguments warnings.
if test "$c_compiler" = "clang"; then
    CFLAGS="$CFLAGS -Qunused-arguments"
fi

# libstdc++ is at the moment the only option as the C++ standard library when compiling with Clang.
# -Wno-c++11-extensions, currently only usable with Clang, suppresses warnings of C++11 extensions in use.
# Suppress unused arguments warnings for C++ files as well.
if test "$cxx_compiler" = "clang++"; then
    CXXFLAGS="$CXXFLAGS -stdlib=libstdc++ -Wno-c++11-extensions -Qunused-arguments"
fi

if test "$host_cpu" = "sh4"; then
    CXXFLAGS="$CXXFLAGS -mieee -w"
    CFLAGS="$CFLAGS -mieee -w"
fi

# Add '-g' flag to gcc to build with debug symbols.
if test "$enable_debug_symbols" = "min"; then
    CXXFLAGS="$CXXFLAGS -g1"
    CFLAGS="$CFLAGS -g1"
elif test "$enable_debug_symbols" != "no"; then
    CXXFLAGS="$CXXFLAGS -g"
    CFLAGS="$CFLAGS -g"
fi

# Add the appropriate 'O' level for optimized builds.
if test "$enable_optimizations" = "yes"; then
    CXXFLAGS="$CXXFLAGS -O2"
    CFLAGS="$CFLAGS -O2"

    if test "$c_compiler" = "gcc"; then
        CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
    fi
    if test "$cxx_compiler" = "g++"; then
        CXXFLAGS="$CXXFLAGS -D_FORTIFY_SOURCE=2"
    fi
else
    CXXFLAGS="$CXXFLAGS -O0"
    CFLAGS="$CFLAGS -O0"
fi