diff --git a/NEWS b/NEWS
index 64e8b825b..696aa4506 100644
--- a/NEWS
+++ b/NEWS
@@ -44,6 +44,7 @@ ver 0.21.24 (not yet released)
 * database
   - simple: fix crash when mounting twice
 * fix unit test failure
+* fix build failure with Android NDK r21
 
 ver 0.21.23 (2020/04/23)
 * protocol
diff --git a/android/build.py b/android/build.py
index 63e57f93e..91e292683 100755
--- a/android/build.py
+++ b/android/build.py
@@ -26,7 +26,7 @@ android_abis = {
         'ndk_arch': 'arm',
         'toolchain_arch': 'arm-linux-androideabi',
         'llvm_triple': 'armv7-linux-androideabi',
-        'cflags': '-march=armv7-a -mfpu=vfp -mfloat-abi=softfp',
+        'cflags': '-fpic -march=armv7-a -mfpu=vfpv3-d16 -mfloat-abi=softfp',
     },
 
     'arm64-v8a': {
@@ -34,7 +34,7 @@ android_abis = {
         'ndk_arch': 'arm64',
         'toolchain_arch': 'aarch64-linux-android',
         'llvm_triple': 'aarch64-linux-android',
-        'cflags': '',
+        'cflags': '-fpic',
     },
 
     'x86': {
@@ -42,7 +42,7 @@ android_abis = {
         'ndk_arch': 'x86',
         'toolchain_arch': 'x86',
         'llvm_triple': 'i686-linux-android',
-        'cflags': '-march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32',
+        'cflags': '-fPIC -march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32',
     },
 
     'x86_64': {
@@ -50,7 +50,7 @@ android_abis = {
         'ndk_arch': 'x86_64',
         'toolchain_arch': 'x86_64',
         'llvm_triple': 'x86_64-linux-android',
-        'cflags': '-m64',
+        'cflags': '-fPIC -m64',
     },
 }
 
@@ -97,7 +97,6 @@ class AndroidNdkToolchain:
         llvm_triple = abi_info['llvm_triple'] + android_api_level
 
         common_flags = '-Os -g'
-        common_flags += ' -fPIC'
         common_flags += ' ' + abi_info['cflags']
 
         toolchain_bin = os.path.join(toolchain_path, 'bin')
diff --git a/python/build/libs.py b/python/build/libs.py
index af018ed8f..0063e220c 100644
--- a/python/build/libs.py
+++ b/python/build/libs.py
@@ -341,8 +341,8 @@ ffmpeg = FfmpegProject(
 )
 
 curl = AutotoolsProject(
-    'http://curl.haxx.se/download/curl-7.69.1.tar.xz',
-    '03c7d5e6697f7b7e40ada1b2256e565a555657398e6c1fcfa4cb251ccd819d4f',
+    'http://curl.haxx.se/download/curl-7.70.0.tar.xz',
+    '032f43f2674008c761af19bf536374128c16241fb234699a55f9fb603fcfbae7',
     'lib/libcurl.a',
     [
         '--disable-shared', '--enable-static',
@@ -397,7 +397,7 @@ libnfs = AutotoolsProject(
 )
 
 boost = BoostProject(
-    'https://dl.bintray.com/boostorg/release/1.72.0/source/boost_1_72_0.tar.bz2',
-    '59c9b274bc451cf91a9ba1dd2c7fdcaf5d60b1b3aa83f2c9fa143417cc660722',
+    'https://dl.bintray.com/boostorg/release/1.73.0/source/boost_1_73_0.tar.bz2',
+    '4eb3b8d442b426dc35346235c8733b5ae35ba431690e38c6a8263dce9fcbb402',
     'include/boost/version.hpp',
 )