Build shared JSI by default (#41037)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/41037

Build JSI as a shared library by default. This avoids running into a
problem with duplicate JSI when building against `libhermes` as a
shared library. This is already the case for React Native on Android.

For RN's iOS builds, explicitly specify that JSI should be statically
linked.

Changelog: [Internal]

Reviewed By: dannysu

Differential Revision: D50294405

fbshipit-source-id: 5e77e6d4ab77f8e338ca5ca4154e879eb3d616d7

packages/react-native/sdks/hermes-engine/utils/build-apple-framework.sh

@@ -86,6 +86,7 @@ function configure_apple_framework {
       -DHERMES_ENABLE_TEST_SUITE:BOOLEAN=false \
       -DHERMES_ENABLE_BITCODE:BOOLEAN=false \
       -DHERMES_BUILD_APPLE_FRAMEWORK:BOOLEAN=true \
+      -DHERMES_BUILD_SHARED_JSI:BOOLEAN=false \
       -DHERMES_BUILD_APPLE_DSYM:BOOLEAN=true \
       -DIMPORT_HERMESC:PATH="$IMPORT_HERMESC_PATH" \
       -DJSI_DIR="$JSI_PATH" \

packages/react-native/sdks/hermes-engine/utils/build-hermes-xcode.sh

@@ -71,6 +71,7 @@ echo "Configure Apple framework"
   -DHERMES_ENABLE_TEST_SUITE:BOOLEAN=false \
   -DHERMES_ENABLE_BITCODE:BOOLEAN=false \
   -DHERMES_BUILD_APPLE_FRAMEWORK:BOOLEAN=true \
+  -DHERMES_BUILD_SHARED_JSI:BOOLEAN=false \
   -DHERMES_BUILD_APPLE_DSYM:BOOLEAN=true \
   -DIMPORT_HERMESC:PATH="${hermesc_path}" \
   -DJSI_DIR="$jsi_path" \