From e4cb720db8b2398b605bc5bae72a28e56686186d Mon Sep 17 00:00:00 2001
From: Geir Sagberg <geir.sagberg@gmail.com>
Date: Sun, 12 Jul 2026 11:15:10 +0200
Subject: [PATCH] Fix Android native math library linkage

---
 src/main/c/h3-java/CMakeLists.txt | 11 ++++++-----
 src/main/c/h3-java/build-h3.sh    |  5 +++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/main/c/h3-java/CMakeLists.txt b/src/main/c/h3-java/CMakeLists.txt
index f0c76e5..7c9278d 100644
--- a/src/main/c/h3-java/CMakeLists.txt
+++ b/src/main/c/h3-java/CMakeLists.txt
@@ -70,11 +70,12 @@ target_link_libraries(h3-java "${H3_BUILD_ROOT}/${H3_CORE_LIBRARY_PATH}${CMAKE_S
 option(H3_JAVA_ANDROID "Whether to enable Android specific build flags")
 if(H3_JAVA_ANDROID)
     target_link_options(h3-java PRIVATE "-Wl,-z,max-page-size=16384")
-endif()
-
-find_library(M_LIB m)
-if(M_LIB)
-    target_link_libraries(h3-java ${M_LIB})
+    target_link_libraries(h3-java m)
+else()
+    find_library(M_LIB m)
+    if(M_LIB)
+        target_link_libraries(h3-java ${M_LIB})
+    endif()
 endif()
 
 find_program(CLANG_FORMAT_PATH clang-format)
diff --git a/src/main/c/h3-java/build-h3.sh b/src/main/c/h3-java/build-h3.sh
index 61f9703..d60935e 100755
--- a/src/main/c/h3-java/build-h3.sh
+++ b/src/main/c/h3-java/build-h3.sh
@@ -211,6 +211,11 @@ for image in $DOCKCROSS_IMAGES; do
     # Perform the actual build inside Docker
     $BUILD_ROOT/dockcross --args "-v $JAVA_HOME:/java" src/main/c/h3-java/build-h3-docker.sh "$BUILD_ROOT" "$UPGRADE_CMAKE" "$CMAKE_ROOT" "$SPECIAL_ANDROID_FLAGS"
 
+    if [[ "$image" == android-* ]]; then
+        $BUILD_ROOT/dockcross readelf -d "$BUILD_ROOT/lib/libh3-java.so" |
+            grep -q 'Shared library: \[libm.so\]'
+    fi
+
     # Copy the built artifact into the source tree so it can be included in the
     # built JAR.
     OUTPUT_ROOT=src/main/resources/$image