build: add Android 16KB page size flags to Makefile

[ajaysehwal]

Change Description

Description of change / link to associated issue.

Android is starting to shift from 4KB to 16KB memory page sizes on newer devices. This change updates the Android build to set the linker max page size to 16KB, ensuring the generated library continues to work correctly across both page-size configurations.

Reference: https://developer.android.com/guide/practices/page-sizes

This PR includes an Android-specific linker flag added to the Makefile:
ANDROID_EXTLDFLAGS := -extldflags=-Wl,-z,max-page-size=16384

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[gemini-code-assist]

Summary of Changes

Hello @ajaysehwal, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request improves the compatibility of the Android build process by adding specific linker flags to support devices that use 16KB memory pages. This change is crucial for ensuring the application functions correctly across a wider range of Android devices, particularly those with non-standard memory page configurations, by preventing potential memory-related issues during runtime.

Highlights

• Android Build Compatibility: Introduced a new ANDROID_EXTLDFLAGS variable in the Makefile to explicitly set the maximum page size to 16KB for Android builds.
• Linker Flags Update: Integrated the ANDROID_EXTLDFLAGS into the ldflags of the gomobile bind command for the Android build target, ensuring the 16KB page size is applied during compilation.

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[gemini-code-assist]

Code Review

This pull request correctly adds the necessary linker flags to the Makefile for building on Android devices with 16KB memory pages. The change is well-contained and follows the existing structure of the Makefile. I've added one suggestion to improve maintainability by extracting the magic number into a named variable.

[gemini-code-assist]

To improve readability and maintainability, it's good practice to avoid magic numbers. Consider extracting 16384 into a named variable. This makes the configuration clearer and easier to modify if needed in the future.

ANDROID_MAX_PAGE_SIZE := 16384
ANDROID_EXTLDFLAGS := -extldflags=-Wl,-z,max-page-size=$(ANDROID_MAX_PAGE_SIZE)

[ziggie1984]

pending CI (can you add this reference somewhere either in the commit msg or in the makefile: https://developer.android.com/guide/practices/page-sizes)

[lightninglabs-deploy]

@ziggie1984: review reminder
@ajaysehwal, remember to re-request review from reviewers when ready