add support for Android NDK unified headers

platform/android/detect.py

@@ -26,6 +26,7 @@ def get_opts():
         EnumVariable('android_arch', 'Target architecture', "armv7", ('armv7', 'armv6', 'arm64v8', 'x86')),
         BoolVariable('android_neon', 'Enable NEON support (armv7 only)', True),
         BoolVariable('android_stl', 'Enable Android STL support (for modules)', False),
+        BoolVariable('ndk_unified_headers', 'Enable NDK unified headers', True)
     ]
 
 
@@ -178,12 +179,28 @@ def configure(env):
     env['RANLIB'] = tools_path + "/ranlib"
     env['AS'] = tools_path + "/as"
 
-    sysroot = env["ANDROID_NDK_ROOT"] + "/platforms/" + env['ndk_platform'] + "/" + env['ARCH']
+    ndk_unified_headers = env['ndk_unified_headers']
+    ndk_version = get_ndk_version(env["ANDROID_NDK_ROOT"])
+
     common_opts = ['-fno-integrated-as', '-gcc-toolchain', gcc_toolchain_path]
 
+    if not ndk_unified_headers and ndk_version != None and ndk_version[0] >= 16:
+        ndk_unified_headers = True
+        print("Turning NDK unified headers on (starting from r16)")
+
+    lib_sysroot = env["ANDROID_NDK_ROOT"] + "/platforms/" + env['ndk_platform'] + "/" + env['ARCH']
+
     ## Compile flags
 
-    env.Append(CPPFLAGS=["-isystem", sysroot + "/usr/include"])
+    if ndk_unified_headers:
+        sysroot = env["ANDROID_NDK_ROOT"] + "/sysroot"
+        env.Append(CPPFLAGS=["-isystem", sysroot + "/usr/include"])
+        env.Append(CPPFLAGS=["-isystem", sysroot + "/usr/include/" + abi_subpath])
+        # For unified headers this define has to be set manually
+        env.Append(CPPFLAGS=["-D__ANDROID_API__=" + str(int(env['ndk_platform'].split("-")[1]))])
+    else:
+        env.Append(CPPFLAGS=["-isystem", lib_sysroot + "/usr/include"])
+
     env.Append(CPPFLAGS='-fpic -ffunction-sections -funwind-tables -fstack-protector-strong -fvisibility=hidden -fno-strict-aliasing'.split())
     env.Append(CPPFLAGS='-DNO_STATVFS -DGLES2_ENABLED'.split())
 
@@ -224,7 +241,7 @@ def configure(env):
 
     ## Link flags
 
-    env['LINKFLAGS'] = ['-shared', '--sysroot=' + sysroot, '-Wl,--warn-shared-textrel']
+    env['LINKFLAGS'] = ['-shared', '--sysroot=' + lib_sysroot, '-Wl,--warn-shared-textrel']
     if env["android_arch"] == "armv7":
         env.Append(LINKFLAGS='-Wl,--fix-cortex-a8'.split())
     env.Append(LINKFLAGS='-Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now'.split())
@@ -248,3 +265,19 @@ def configure(env):
         if (env["android_arch"] == "armv6" or env["android_arch"] == "armv7"):
             env.Append(CFLAGS=["-DOPUS_ARM_OPT"])
         env.opus_fixed_point = "yes"
+
+# Return NDK version as [<major>,<minor>,<build>] or None if cannot be figured out (adapted from the Chromium project).
+def get_ndk_version (path):
+    if path == None:
+        return None
+    prop_file_path = os.path.join(path, "source.properties")
+    try:
+        with open(prop_file_path) as prop_file:
+            for line in prop_file:
+                key_value = map(lambda x: string.strip(x), line.split("="))
+                if key_value[0] == "Pkg.Revision":
+                    version_parts = key_value[1].split("-")[0].split(".")
+                    return map(int, version_parts[0:3])
+    except:
+        print("Could not read source prop file '%s'" % prop_file_path)
+    return None

platform/android/platform_config.h

@@ -28,3 +28,4 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 #include <alloca.h>
+#include <malloc.h>