datapath-windows: Code refactoring and fixes in Vport.c

[cascardo/ovs.git] / INSTALL.md

diff --git a/INSTALL.md b/INSTALL.md
index b2b0cbb..9f8c57e 100644 (file)
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -45,8 +45,6 @@ you will need the following software:
 
   - Python 2.x, for x >= 4.
 
-  - patch (The utility that is used to patch files).
-
 On Linux, you may choose to compile the kernel module that comes with
 the Open vSwitch distribution or to use the kernel module built into
 the Linux kernel (version 3.3 or later).  See the [FAQ.md] question
@@ -196,6 +194,20 @@ 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"`
+
+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"
+
 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
@@ -259,6 +271,10 @@ Building the Sources
    For improved warnings if you installed "sparse" (see "Prerequisites"),
    add C=1 to the command line.
 
+   Some versions of Clang and ccache are not completely compatible.
+   If you see unusual warnings when you use both together, consider
+   disabling ccache for use with Clang.
+
 2. Consider running the testsuite.  Refer to "Running the Testsuite"
    below, for instructions.