[build] Fixed ENABLE_MONOTONIC_CLOCK=ON when target is Android

CMakeLists.txt

@@ -39,7 +39,8 @@ set_if(LINUX       ${CMAKE_SYSTEM_NAME} MATCHES "Linux")
 set_if(BSD         ${SYSNAME_LC} MATCHES "bsd$")
 set_if(MICROSOFT   WIN32 AND (NOT MINGW AND NOT CYGWIN))
 set_if(GNU         ${CMAKE_SYSTEM_NAME} MATCHES "GNU")
-set_if(POSIX       LINUX OR DARWIN OR BSD OR (CYGWIN AND CYGWIN_USE_POSIX))
+set_if(ANDROID     ${CMAKE_SYSTEM_NAME} MATCHES "ANDROID")
+set_if(POSIX       LINUX OR DARWIN OR BSD OR ANDROID OR (CYGWIN AND CYGWIN_USE_POSIX))
 set_if(SYMLINKABLE LINUX OR DARWIN OR BSD OR CYGWIN OR GNU)
 
 # Not sure what to do in case of compiling by MSVC.
@@ -114,7 +115,7 @@ set(ENABLE_MONOTONIC_CLOCK_DEFAULT OFF)
 set(MONOTONIC_CLOCK_LINKLIB "")
 if (MICROSOFT)
 	set(ENABLE_STDCXX_SYNC_DEFAULT ON)
-elseif (LINUX)
+elseif (POSIX)
 	test_requires_clock_gettime(ENABLE_MONOTONIC_CLOCK_DEFAULT MONOTONIC_CLOCK_LINKLIB)
 endif()