Save build timestamps in Android builds

* java/Makefile.in (install_temp/assets/build_info): New
rule.:(emacs.apk-in): Depend on that file.
* lisp/version.el (android-read-build-system)
(android-read-build-time): New functions.
(emacs-build-system, emacs-build-time): Use those functions on
Android, as dumping is done after installation on Android.
* src/fileio.c (Finsert_file_contents):
* src/window.c (replace_buffer_in_windows): Don't call functions
if they are not defined, which can happen during loadup.

1 files changed, 5 insertions, 1 deletions

diff --git a/java/Makefile.in b/java/Makefile.in
index c7fe6e07c77..1a7852487ef 100644
--- a/java/Makefile.in
+++ b/java/Makefile.in
@@ -222,8 +222,12 @@ install_temp/assets/version: install_temp
                         && (git rev-parse --abbrev-ref HEAD             \
                             || echo "Unknown") } 2> /dev/null > $@
 
+install_temp/assets/build_info: install_temp
+        $(AM_V_GEN) { hostname; date +%s; } > $@
+
 emacs.apk-in: install_temp install_temp/assets/directory-tree \
-  install_temp/assets/version AndroidManifest.xml
+  install_temp/assets/version install_temp/assets/build_info  \
+  AndroidManifest.xml
 # Package everything.  Specifying the assets on this command line is
 # necessary for AAssetManager_getNextFileName to work on old versions
 # of Android.  Make sure not to generate R.java, as it's already been