Support 16 KB page sizes

Author: mhsmith

android-env.sh

@@ -24,11 +24,11 @@ fail() {
 # * https://android.googlesource.com/platform/ndk/+/ndk-rXX-release/docs/BuildSystemMaintainers.md
 #   where XX is the NDK version. Do a diff against the version you're upgrading from, e.g.:
 #   https://android.googlesource.com/platform/ndk/+/ndk-r25-release..ndk-r26-release/docs/BuildSystemMaintainers.md
-ndk_version=26.2.11394342
+ndk_version=27.1.12297006
 
 ndk=$ANDROID_HOME/ndk/$ndk_version
 if ! [ -e $ndk ]; then
-    log "Installing NDK: this may take several minutes"
+    log "Installing NDK - this may take several minutes"
     yes | $ANDROID_HOME/cmdline-tools/latest/bin/sdkmanager "ndk;$ndk_version"
 fi
 
@@ -58,10 +58,16 @@ for path in "$AR" "$AS" "$CC" "$CXX" "$LD" "$NM" "$RANLIB" "$READELF" "$STRIP";
     fi
 done
 
-export CFLAGS=""
-export LDFLAGS="-Wl,--build-id=sha1 -Wl,--no-rosegment"
+export CFLAGS="-D__BIONIC_NO_PAGE_SIZE_MACRO"
+export LDFLAGS="-Wl,--build-id=sha1 -Wl,--no-rosegment -Wl,-z,max-page-size=16384"
 
-# Many packages get away with omitting this on standard Linux, but Android is stricter.
+# Unlike Linux, Android does not implicitly use a dlopened library to resolve
+# relocations in subsequently-loaded libraries, even if RTLD_GLOBAL is used
+# (https://github.com/android/ndk/issues/1244). So any library that fails to
+# build with this flag, would also fail to load at runtime.
+LDFLAGS="$LDFLAGS -Wl,--no-undefined"
+
+# Many packages get away with omitting -lm on Linux, but Android is stricter.
 LDFLAGS="$LDFLAGS -lm"
 
 # -mstackrealign is included where necessary in the clang launcher scripts which are
@@ -72,8 +78,12 @@ fi
 
 if [ -n "${PREFIX:-}" ]; then
     abs_prefix=$(realpath $PREFIX)
-    CFLAGS+=" -I$abs_prefix/include"
-    LDFLAGS+=" -L$abs_prefix/lib"
+
+    # Use -idirafter so that package-specified -I directories take priority. For
+    # example, grpcio provides its own BoringSSL headers which must be used rather than
+    # our OpenSSL.
+    CFLAGS="$CFLAGS -idirafter $abs_prefix/include"
+    LDFLAGS="$LDFLAGS -L$abs_prefix/lib"
 
     export PKG_CONFIG="pkg-config --define-prefix"
     export PKG_CONFIG_LIBDIR="$abs_prefix/lib/pkgconfig"