+# We may use the may_alias attribute if __GNUC__ is defined, so
+# if the compiler defines __GNUC__ but does not provide it,
+# it must be defined away as part of the CFLAGS.
+#
+printf "checking whether compiler needs attribute((may_alias)) suppression... "
+cat > "$tmpc" <<EOF
+typedef int
+#ifdef __GNUC__
+__attribute__((__may_alias__))
+#endif
+x;
+EOF
+if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS \
+ -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "no\n"
+else
+printf "yes\n"
+CFLAGS_C99FSE="$CFLAGS_C99FSE -D__may_alias__="
+fi
+
+#
+# The GNU toolchain defaults to assuming unmarked files need an
+# executable stack, potentially exposing vulnerabilities in programs
+# linked with such object files. Fix this.
+#
+tryflag CFLAGS_C99FSE -Wa,--noexecstack
+
+#
+# Check for options to disable stack protector, which needs to be
+# disabled for a few early-bootstrap translation units. If not found,
+# this is not an error; we assume the toolchain does not do ssp.
+#
+tryflag CFLAGS_NOSSP -fno-stack-protector
+
+#
+# Check for options that may be needed to prevent the compiler from
+# generating self-referential versions of memcpy,, memmove, memcmp,
+# and memset. Really, we should add a check to determine if this
+# option is sufficient, and if not, add a macro to cripple these
+# functions with volatile...
+#
+tryflag CFLAGS_MEMOPS -fno-tree-loop-distribute-patterns
+
+#
+# Enable debugging if requessted.
+#
+test "$debug" = yes && CFLAGS_AUTO=-g
+
+#
+# Preprocess asm files to add extra debugging information if debug is
+# enabled, our assembler supports the needed directives, and the
+# preprocessing script has been written for our architecture.