Added INSTALL_CHANGE and INSTALL_VARIANT information.

make/README

@@ -428,7 +428,7 @@
                 The following commands should only be called
                 as make variables:
 
-                    MAKE,INSTALL,SHELL
+                    MAKE,INSTALL,INSTALL_VARIANT,SHELL
 
                     ECHO,CAT,CP,MV,LN,MKDIR,CHMOD
 
@@ -437,6 +437,29 @@
                     CC,CPP,AS,AR,LD,NM,SIZE,RANLIB,MKLIB,
                     YACC,LEX,LINT,CTAGS,ETAGS
 
+                 In addition, the following commands specifically support
+                 the installation of libraries, executables, header files,
+                 and other things that need to be installed:
+
+                    INSTALL_CHANGE  - install a file only if the source
+                                      file is actually different than
+                                      the installed copy or if there is
+                                      no installed copy.  USAGE:
+
+      usage: install-if-change [ -vmV ] file [ file ... ] dest-directory-or-file
+	-v	    -- verbose
+        -V suffix   -- suffix to append to targets (before any . suffix)
+                        eg: -V _g would change 'foo' to 'foo_g' and
+                                               'libfoo.a' to 'libfoo_g.a'
+        -m mode     -- mode for new file(s)
+
+                    INSTALL_VARIANT - installs the built file using the
+                                      proper variant suffix (e.g. _g
+                                      for debug turns libmine.a into libmine_g.a)
+                                      This is implemented as a macro that
+                                      invokes install-if-change with the
+                                      appropriate -V argument setting.
+
             Special Directory Makefile Targets
             ----------------------------------
 
@@ -469,3 +492,4 @@
 
 
     
+