INSTALL.md: Document how to add custom compiler flags.

CC: Mark B Kavanagh <mark.b.kavanagh@intel.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Russell Bryant <rbryant@redhat.com>

diff --git a/INSTALL.md b/INSTALL.md
index 3762e00..d060171 100644 (file)
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -196,6 +196,14 @@ To use 'clang' compiler:
 
       `% ./configure CC=clang`
 
+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"`
+
 To build the Linux kernel module, so that you can run the
 kernel-based switch, pass the location of the kernel build
 directory on --with-linux.  For example, to build for a running