cmake - add option for assertions

Signed-off-by: Ralph Giles <giles@thaumas.net>

CMakeLists.txt

@@ -55,6 +55,10 @@ set(OPUS_FLOAT_APPROX_HELP_STR "enable floating point approximations (Ensure you
 option(OPUS_FLOAT_APPROX ${OPUS_FLOAT_APPROX_HELP_STR} OFF)
 add_feature_info(OPUS_FLOAT_APPROX OPUS_FLOAT_APPROX ${OPUS_FLOAT_APPROX_HELP_STR})
 
+set(OPUS_ASSERTIONS_HELP_STR "additional software error checking.")
+option(OPUS_ASSERTIONS ${OPUS_ASSERTIONS_HELP_STR} OFF)
+add_feature_info(OPUS_ASSERTIONS OPUS_ASSERTIONS ${OPUS_ASSERTIONS_HELP_STR})
+
 set(OPUS_INSTALL_PKG_CONFIG_MODULE_HELP_STR "install pkg-config module.")
 option(OPUS_INSTALL_PKG_CONFIG_MODULE ${OPUS_INSTALL_PKG_CONFIG_MODULE_HELP_STR} ON)
 add_feature_info(OPUS_INSTALL_PKG_CONFIG_MODULE OPUS_INSTALL_PKG_CONFIG_MODULE ${OPUS_INSTALL_PKG_CONFIG_MODULE_HELP_STR})
@@ -265,6 +269,10 @@ if(OPUS_FLOAT_APPROX)
   target_compile_definitions(opus PRIVATE FLOAT_APPROX)
 endif()
 
+if(OPUS_ASSERTIONS)
+  target_compile_definitions(opus PRIVATE ENABLE_ASSERTIONS)
+endif()
+
 if(OPUS_VAR_ARRAYS)
   target_compile_definitions(opus PRIVATE VAR_ARRAYS)
 elseif(OPUS_USE_ALLOCA)