INSTALL: Describe dependency knobs from Makefile

[git.git] / INSTALL

diff --git a/INSTALL b/INSTALL
index 7ab2580ede1d8d8a1697e02882b7f4f65a0cb5d3..be504c95e1f092edaf524064d49ba30adc57dc9b 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -13,6 +13,10 @@ that uses $prefix, the built results have some paths encoded,
 which are derived from $prefix, so "make all; make prefix=/usr
 install" would not work.
 
+The beginning of the Makefile documents many variables that affect the way
+git is built.  You can override them either from the command line, or in a
+config.mak file.
+
 Alternatively you can use autoconf generated ./configure script to
 set up install paths (via config.mak.autogen), so you can write instead
 
@@ -48,7 +52,9 @@ Issues of note:
        export GIT_EXEC_PATH PATH GITPERLLIB
 
  - Git is reasonably self-sufficient, but does depend on a few external
-   programs and libraries:
+   programs and libraries.  Git can be used without most of them by adding
+   the approriate "NO_<LIBRARY>=YesPlease" to the make command line or
+   config.mak file.
 
        - "zlib", the compression library. Git won't build without it.
 
@@ -59,25 +65,29 @@ Issues of note:
 
        - "Perl" is needed to use some of the features (e.g. preparing a
          partial commit using "git add -i/-p", interacting with svn
-         repositories with "git svn").
+         repositories with "git svn").  If you can live without these, use
+         NO_PERL.
 
-       - "openssl".  Unless you specify otherwise, you'll get the SHA1
-         library from here.
+       - "openssl" library is used by git-imap-send to use IMAP over SSL.
+         If you don't need it, use NO_OPENSSL.
 
-         If you don't have openssl, you can use one of the SHA1 libraries
-         that come with git (git includes one inspired by Mozilla's and a
-         PowerPC optimized one too - see the Makefile).
+         By default, git uses OpenSSL for SHA1 but it will use it's own
+         library (inspired by Mozilla's) with either NO_OPENSSL or
+         BLK_SHA1.  Also included is a version optimized for PowerPC
+         (PPC_SHA1).
 
-       - libcurl library; git-http-fetch and git-fetch use them.  You
+       - "libcurl" library is used by git-http-fetch and git-fetch.  You
          might also want the "curl" executable for debugging purposes.
-         If you do not use http transfer, you are probably OK if you
-         do not have them.
+         If you do not use http:// or https:// repositories, you do not
+         have to have them (use NO_CURL).
 
-       - expat library; git-http-push uses it for remote lock
-         management over DAV.  Similar to "curl" above, this is optional.
+       - "expat" library; git-http-push uses it for remote lock
+         management over DAV.  Similar to "curl" above, this is optional
+         (with NO_EXPAT).
 
-        - "wish", the Tcl/Tk windowing shell is used in gitk to show the
-          history graphically, and in git-gui.
+       - "wish", the Tcl/Tk windowing shell is used in gitk to show the
+         history graphically, and in git-gui.  If you don't want gitk or
+         git-gui, you can use NO_TCLTK.
 
  - Some platform specific issues are dealt with Makefile rules,
    but depending on your specific installation, you may not