android: Use property instead of ANDROID_NDK_HOME env var

Write an `ndk.dir` property with the directory path to
`android/source/local.properties` instead, similar
to how it's done for `sdk.dir`.

Also, rename the `ANDROID_NDK_HOME` variable that's
assigned in configure.ac that holds the corresponding
value to `ANDROID_NDK_DIR`, because the gradle warning
still shows up if that environment variable is set in
addition to having an `ndk.dir` property in `local.properties`.

This makes the following gradle warning disappear:

> > Task :stripStrippedUIDebugDebugSymbols
> WARNING: Support for ANDROID_NDK_HOME is deprecated and will be removed in the future. Use android.ndkVersion in build.gradle instead.
> Support for ANDROID_NDK_HOME is deprecated and will be removed in the future. Use android.ndkVersion in build.gradle instead.

Note however, that with this approach of using the `ndk.dir`
property instead of the suggested `android.ndkVersion`
(with the latter having the stricter requirement that
the `ndk` dir would have to be a subdir of the SDK dir),
doing the actual upgrade to a newer Gradle (plugin) version
in follow-up commit
Change-Id Ia982d72d877e229c3006c6d528b830d16c88481f
"android: Update Android Gradle Plugin to 7.1.3"
revealed that the use of the `ndk.dir` property
is deprecated in newer Gradle (plugin) versions as well,
resulting in this warning.

> > Task :stripStrippedUIDebugDebugSymbols
> [CXX5106] NDK was located by using ndk.dir property. This method is
> deprecated and will be removed in a future release. Please delete
> ndk.dir from local.properties and set android.ndkVersion to
> [20.0.5594570] in all native modules in the project.
> https://developer.android.com/r/studio-ui/ndk-dir

It might make sense to address that in a follow-up step,
but for now, it's an improvement and keeps it working
after the upgrade without potentially causing any incompatibility
problems with existing autogen configurations,
while support for the `ANDROID_NDK_HOME` env var that was
used so far seems to have been dropped, resulting in

> > Task :stripStrippedUIDebugDebugSymbols
> Unable to strip the following libraries, packaging them as they are:
> libc++_shared.so, libfreebl3.so, liblo-native-code.so, libnspr4.so,
> libnss3.so, libnssckbi.so, libnssdbm3.so, libnssutil3.so,
> libplc4.so, libplds4.so, libsmime3.so, libsoftokn3.so,
> libsqlite3.so, libssl3.so.

instead if upgrading gradle without switching to the use of the property.

Change-Id: I4a090e8736dac80777f69b0e12819b9c056f582b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/133177
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/android/Bootstrap/Makefile.shared b/android/Bootstrap/Makefile.shared
index f40693615f0a..18082ea30ea3 100644
--- a/android/Bootstrap/Makefile.shared
+++ b/android/Bootstrap/Makefile.shared
@@ -23,7 +23,8 @@ OBJLOCAL=$(BUILDDIR)/android/obj/local/$(ANDROID_APP_ABI)
 #
 
 local.properties: $(BUILDDIR)/config_host.mk
-	echo sdk.dir=$(ANDROID_SDK_HOME) >local.properties
+	echo ndk.dir=$(ANDROID_NDK_DIR) >local.properties
+	echo sdk.dir=$(ANDROID_SDK_HOME) >>local.properties
 
 #
 # Build / link the single .so for this app
@@ -71,7 +72,7 @@ $(SODEST)/nss-libraries :
 	mkdir -p $(SODEST)
 	$(foreach lib,$(NSSLIBS),$(STRIP) -o $(SODEST)/lib$(lib).so $(INSTDIR)/$(LIBO_LIB_FOLDER)/lib$(lib).so;)
 
-$(SODEST)/libc++_shared.so : $(ANDROID_NDK_HOME)/sources/cxx-stl/llvm-libc++/libs/$(ANDROID_APP_ABI)/libc++_shared.so
+$(SODEST)/libc++_shared.so : $(ANDROID_NDK_DIR)/sources/cxx-stl/llvm-libc++/libs/$(ANDROID_APP_ABI)/libc++_shared.so
 	mkdir -p $(SODEST)
 	cp $< $@