Fix crash issue for API < 21

Summary:
    New NDK seems not define __ANDROID_API__ so that `sigfillset` does
    not go for fallback path and crash.

    Define __ANDROID_API__ explicitly to fix the issue.

Author: Kudo

scripts/.tests.env

@@ -10,7 +10,7 @@ export ANDROID_SDK_BUILD_API_LEVEL="28"
 # Google APIs for Android level
 export ANDROID_GOOGLE_API_LEVEL="23"
 # Minimum Android API Level we target
-export ANDROID_SDK_TARGET_API_LEVEL="21"
+export ANDROID_SDK_TARGET_API_LEVEL="16"
 # Android Virtual Device name
 export AVD_NAME="testAVD"
 # ABI to use in Android Virtual Device

scripts/compile/common.sh

@@ -149,6 +149,7 @@ $FRAME_POINTER_FLAG \
 -DCUSTOMIZE_REACT_NATIVE \
 $SWITCH_COMMON_CFLAGS_INTL \
 $CFLAGS_BUILD_TYPE \
+-D__ANDROID_API__=${ANDROID_API} \
 "
 
 COMMON_CXXFLAGS=" \

scripts/compile/jsc.sh

@@ -65,7 +65,7 @@ $TARGETDIR/webkit/Tools/Scripts/build-webkit \
   --no-tools \
   --cmakeargs="-DCMAKE_TOOLCHAIN_FILE=${ANDROID_NDK}/build/cmake/android.toolchain.cmake \
   -DANDROID_ABI=${JNI_ARCH} \
-  -DANDROID_NATIVE_API_LEVEL=${ANDROID_API} \
+  -DANDROID_PLATFORM=${ANDROID_API} \
   -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=BOTH \
   -DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE=BOTH \
   -DICU_ROOT=${TARGETDIR}/icu/${CROSS_COMPILE_PLATFORM}-${FLAVOR}/prebuilts \