change build scripts to make reproducible builds possible

- makes SOURCE_DATE_EPOCH affect BUILDDATE and version string
- makes wpsbuild.pl output deterministic
- omits unnecessary extended metadata from zip files
- runs strip-nondeterminism on zip files if REPRODUCIBLE_ZIP is set

Change-Id: I1617e3f5233b2bc356fcfa6457be1a7785c303f9

tools/buildzip.pl

@@ -259,7 +259,7 @@ GetOptions ( 'r|root=s'      => \$ROOT,
 # Thus we use the ":" for those for which we use a default value in case of ""
 # and assign the default value afterwards
 if ($ziptool eq '') {
-    $ziptool = "zip -r9";
+    $ziptool = "zip -r9 -X";
 }
 if ($output eq '') {
     $output = "rockbox.zip"

tools/configure

@@ -4915,7 +4915,11 @@ export BUILDDIR=${pwd}
 export RBCODEC_BLD=${pwd}/lib/rbcodec
 export VOICELANGUAGE=${voicelanguage}
 export MEMORYSIZE=${memory}
+ifeq (\$(SOURCE_DATE_EPOCH),)
 export BUILDDATE:=\$(shell date -u +'-DYEAR=%Y -DMONTH=%m -DDAY=%d')
+else
+export BUILDDATE:=\$(shell date -d "@\$(SOURCE_DATE_EPOCH)" -u +'-DYEAR=%Y -DMONTH=%m -DDAY=%d')
+endif
 export MKFIRMWARE=${tool}
 export BMP2RB_MONO=${bmp2rb_mono}
 export BMP2RB_NATIVE=${bmp2rb_native}

tools/root.make

@@ -351,6 +351,9 @@ $(BUILDDIR)/rockbox.zip: build
 endif
 	$(call PRINTS,ZIP rockbox$(ZIPFILESUFFIX).zip)
 	$(SILENT)$(TOOLSDIR)/buildzip.pl $(VERBOSEOPT) --app=$(APPLICATION) -m \"$(MODELNAME)\" -i \"$(TARGET_ID)\" -o $(BUILDDIR)/rockbox$(ZIPFILESUFFIX).zip -r "$(ROOTDIR)" --rbdir="$(RBDIR)" $(BUILDZIPOPTS) $(TARGET) $(BINARY)
+ifneq ($(REPRODUCIBLE_ZIP),)
+	$(SILENT)strip-nondeterminism $(BUILDDIR)/rockbox$(ZIPFILESUFFIX).zip
+endif
 
 mapzip:
 	$(SILENT)find . -name "*.map" | xargs zip rockbox-maps.zip

tools/version.sh

@@ -50,7 +50,11 @@ if [ -z $VERSION ]; then
         # Ok, we need to derive it from the Version Control system
 	    VER=`gitversion $TOP`
     fi
-VERSION=$VER-`date -u +%y%m%d`
+if [ -z $SOURCE_DATE_EPOCH ]; then
+	VERSION=$VER-`date -u +%y%m%d`
+else
+	VERSION=$VER-`date -d @$SOURCE_DATE_EPOCH -u +%y%m%d`
+fi
 fi
 echo $VERSION