tools: Remove install-if-change program

The last installed tool in RTEMS repository is the install-if-change
script.  It is not used to build/install BSPs.  This script does the
same as the standard "install" program with an additional feature to
install variants via the -V command line option.

This script is used by the standard Makefile support:

c/src/make/host.cfg.in:INSTALL_CHANGE=$(PROJECT_BIN)/install-if-change

The INSTALL_CHANGE is used by:

c/src/make/host.cfg.in:ifndef INSTALL_CHANGE
c/src/make/host.cfg.in:INSTALL_CHANGE=$(PROJECT_BIN)/install-if-change
c/src/make/host.cfg.in:INSTALL_VARIANT=$(INSTALL_CHANGE) -V
"$(LIB_VARIANT)"

Remove the support for variant installation and instead use the standard
"install" program.  This breaks application Makefiles using the standard
Makefile support of RTEMS.

Close #3455.

c/src/make/README

@@ -426,24 +426,9 @@
                  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:
+                    INSTALL_CHANGE  - set to host "install" program by default
 
-      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.
+                    INSTALL_VARIANT - set to host "install" program by default
 
             Special Directory Makefile Targets
             ----------------------------------

c/src/make/host.cfg.in

@@ -28,9 +28,11 @@ BIN2C=rtems-bin2c
 endif
 
 ifndef INSTALL_CHANGE
-INSTALL_CHANGE=$(PROJECT_BIN)/install-if-change
+INSTALL_CHANGE=install
+endif
+ifndef INSTALL_VARIANT
+INSTALL_VARIANT=install
 endif
-INSTALL_VARIANT=$(INSTALL_CHANGE) -V "$(LIB_VARIANT)"
 
 # ksh (or bash) is used by some shell scripts; ref build-tools/scripts/Makefile
 #