+To supply special flags to the C compiler, specify them as CFLAGS on
+the configure command line. If you want the default CFLAGS, which
+include "-g" to build debug symbols and "-O2" to enable optimizations,
+you must include them yourself. For example, to build with the
+default CFLAGS plus "-mssse3", you might run configure as follows:
+
+ `% ./configure CFLAGS="-g -O2 -mssse3"`
+
+Note that these CFLAGS are not applied when building the Linux
+kernel module. Custom CFLAGS for the kernel module are supplied
+using the EXTRA_CFLAGS variable when running make. So, for example:
+
+ `% make EXTRA_CFLAGS="-Wno-error=date-time"
+