Add missing patch

ilbc-flags.patch

@@ -0,0 +1,21 @@
+diff -Naur libilbc-3.0.4.old/CMakeLists.txt libilbc-3.0.4/CMakeLists.txt
+--- libilbc-3.0.4.old/CMakeLists.txt	2022-05-25 10:51:43.530630048 +0200
++++ libilbc-3.0.4/CMakeLists.txt	2022-05-25 10:52:59.434028167 +0200
+@@ -52,15 +52,11 @@
+ 
+ if((CMAKE_C_COMPILER_ID STREQUAL "GNU") OR
+    (CMAKE_C_COMPILER_ID MATCHES "Clang" AND CMAKE_C_COMPILER_FRONTEND_VARIANT STREQUAL "GNU"))
+-    set(CMAKE_C_FLAGS "-Wall -Wextra -Wmissing-prototypes -Wstrict-prototypes -Wno-unused-parameter -fno-strict-aliasing")
+-    set(CMAKE_C_FLAGS_DEBUG "-g")
+-    set(CMAKE_C_FLAGS_RELEASE "-O2")
++    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+ endif()
+ if((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") OR
+    (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU"))
+-    set(CMAKE_CXX_FLAGS "-Wall -Wextra -Wno-unused-parameter -fno-strict-aliasing")
+-    set(CMAKE_CXX_FLAGS_DEBUG "-g")
+-    set(CMAKE_CXX_FLAGS_RELEASE "-O2")
++    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+ endif()
+ 
+ if(CMAKE_C_COMPILER_ID STREQUAL "MSVC")