Document how the configuration option 'reconf' works

[openssl.git] / INSTALL

diff --git a/INSTALL b/INSTALL
index 4e954e34c2f37d309346398f03a61b2065d14388..558381770b2281e20a112b5bb8e4d230ae987350 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -512,9 +512,9 @@
                    Build without support for the specified algorithm, where
                    <alg> is one of: bf, blake2, camellia, cast, chacha, cmac,
                    des, dh, dsa, ecdh, ecdsa, idea, md4, mdc2, ocb, poly1305,
-                                  rc2, rc4, rmd160, scrypt, seed, siphash, sm3, sm4 or
-                                  whirlpool.  The "ripemd" algorithm is deprecated and if used
-                                  is synonymous with rmd160.
+                   rc2, rc4, rmd160, scrypt, seed, siphash, sm3, sm4 or
+                   whirlpool.  The "ripemd" algorithm is deprecated and if used
+                   is synonymous with rmd160.
 
   -Dxxx, lxxx, -Lxxx, -Wl, -rpath, -R, -framework, -static
                    These system specific options will be recognised and
@@ -532,6 +532,30 @@
                    passed through as they are to the compiler as well.  Again,
                    consult your compiler documentation.
 
+  VAR=value
+                   Assignment if environment variable for Configure.  These
+                   work just like normal environment variable assignments,
+                   but are supported on all platforms and are confined to
+                   the configuration scripts only.  These assignments override
+                   the corresponding value in the inherited environment, if
+                   there is one.
+
+  reconf
+  reconfigure
+                   Reconfigure from earlier data.  This fetches the previous
+                   command line options and environment from data saved in
+                   "configdata.pm", and runs the configuration process again,
+                   using these options and environment.
+                   Note: NO other option is permitted together with "reconf".
+                   This means that you also MUST use "./Configure" (or
+                   what corresponds to that on non-Unix platforms) directly
+                   to invoke this option.
+                   Note: The original configuration saves away values for ALL
+                   environment variables that were used, and if they weren't
+                   defined, they are still saved away with information that
+                   they weren't originally defined.  This information takes
+                   precedence over environment variables that are defined
+                   when reconfiguring.
 
  Installation in Detail
  ----------------------