Add option of using blocking random

CMakeLists.txt

@@ -4,6 +4,7 @@ project("sodium")
 
 option(SODIUM_DISABLE_TESTS "Disable tests" OFF)
 option(SODIUM_MINIMAL "Only compile the minimum set of functions required for the high-level API" OFF)
+option(SODIUM_ENABLE_BLOCKING_RANDOM "Enable this switch only if /dev/urandom is totally broken on the target platform" OFF)
 
 add_library(${PROJECT_NAME}
     libsodium/src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
@@ -267,6 +268,7 @@ target_compile_definitions(${PROJECT_NAME}
         $<$<BOOL:${SODIUM_MINIMAL}>:SODIUM_LIBRARY_MINIMAL>
     PRIVATE
         $<$<BOOL:${BUILD_SHARED_LIBS}>:SODIUM_DLL_EXPORT>
+        $<$<BOOL:${SODIUM_ENABLE_BLOCKING_RANDOM}>:USE_BLOCKING_RANDOM>
         $<$<BOOL:${SODIUM_MINIMAL}>:MINIMAL>
 )