cmake, refactor: Rename try_add_compile_option to try_append_cflags

Actually, `try_append_cflags()` can handle a list of flags, and the new
name is similar to the one used in `configure.ac`.

CMakeLists.txt

@@ -182,25 +182,25 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING "Choose the type of build." FORCE)
 endif()
 
-include(TryAddCompileOption)
+include(TryAppendCFlags)
 if(MSVC)
-  try_add_compile_option(/W2)
-  try_add_compile_option(/wd4146)
+  try_append_c_flags(/W2)
+  try_append_c_flags(/wd4146)
 else()
-  try_add_compile_option(-pedantic)
-  try_add_compile_option(-Wall)
-  try_add_compile_option(-Wcast-align)
-  try_add_compile_option(-Wcast-align=strict)
-  try_add_compile_option(-Wconditional-uninitialized)
-  try_add_compile_option(-Wextra)
-  try_add_compile_option(-Wnested-externs)
-  try_add_compile_option(-Wno-long-long)
-  try_add_compile_option(-Wno-overlength-strings)
-  try_add_compile_option(-Wno-unused-function)
-  try_add_compile_option(-Wreserved-identifier)
-  try_add_compile_option(-Wshadow)
-  try_add_compile_option(-Wstrict-prototypes)
-  try_add_compile_option(-Wundef)
+  try_append_c_flags(-pedantic)
+  try_append_c_flags(-Wall)
+  try_append_c_flags(-Wcast-align)
+  try_append_c_flags(-Wcast-align=strict)
+  try_append_c_flags(-Wconditional-uninitialized)
+  try_append_c_flags(-Wextra)
+  try_append_c_flags(-Wnested-externs)
+  try_append_c_flags(-Wno-long-long)
+  try_append_c_flags(-Wno-overlength-strings)
+  try_append_c_flags(-Wno-unused-function)
+  try_append_c_flags(-Wreserved-identifier)
+  try_append_c_flags(-Wshadow)
+  try_append_c_flags(-Wstrict-prototypes)
+  try_append_c_flags(-Wundef)
 endif()
 
 set(CMAKE_C_VISIBILITY_PRESET hidden)

cmake/TryAddCompileOption.cmake → cmake/TryAppendCFlags.cmake

@@ -1,7 +1,7 @@
 include(CheckCCompilerFlag)
 
 # Append flags to the COMPILE_OPTIONS directory property if CC accepts them.
-macro(try_add_compile_option)
+macro(try_append_c_flags)
   secp256k1_check_c_flags_internal("${ARGV}" result)
   if(result)
     add_compile_options(${ARGV})