Install applink.c with the public header files.

This is only done for the platforms where 'OPENSSL_USE_APPLINK' is defined.

Also, change the docs of OPENSSL_Applink to say where to find applink.c
in the installation directory.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/Configurations/unix-Makefile.tmpl b/Configurations/unix-Makefile.tmpl
index 567e2af..ac7fe43 100644
--- a/Configurations/unix-Makefile.tmpl
+++ b/Configurations/unix-Makefile.tmpl
@@ -342,6 +342,11 @@
 	@[ -n "$(INSTALLTOP)" ] || (echo INSTALLTOP should not be empty; exit 1)
 	@echo "*** Installing development files"
 	@$(PERL) $(SRCDIR)/util/mkdir-p.pl $(DESTDIR)$(INSTALLTOP)/include/openssl
+	@ : {- output_off() unless grep { $_ eq "OPENSSL_USE_APPLINK" } @{$target{defines}}; "" -}
+	@echo "install $(SRCDIR)/ms/applink.c -> $(DESTDIR)$(INSTALLTOP)/include/openssl/applink.c"
+	@cp $(SRCDIR)/ms/applink.c $(DESTDIR)$(INSTALLTOP)/include/openssl/applink.c
+	@chmod 644 $(DESTDIR)$(INSTALLTOP)/include/openssl/applink.c
+	@ : {- output_on() unless grep { $_ eq "OPENSSL_USE_APPLINK" } @{$target{defines}}; "" -}
 	@set -e; for i in $(SRCDIR)/include/openssl/*.h \
 			  $(BLDDIR)/include/openssl/*.h; do \
 		fn=`basename $$i`; \
@@ -397,6 +402,10 @@
 
 uninstall_dev:
 	@echo "*** Uninstalling development files"
+	@ : {- output_off() unless grep { $_ eq "OPENSSL_USE_APPLINK" } @{$target{defines}}; "" -}
+	@echo "$(RM) $(DESTDIR)$(INSTALLTOP)/include/openssl/applink.c"
+	@$(RM) $(DESTDIR)$(INSTALLTOP)/include/openssl/applink.c
+	@ : {- output_on() unless grep { $_ eq "OPENSSL_USE_APPLINK" } @{$target{defines}}; "" -}
 	@set -e; for i in $(SRCDIR)/include/openssl/*.h \
 			  $(BLDDIR)/include/openssl/*.h; do \
 		fn=`basename $$i`; \