add WARNINGS_AS_ERRORS cmake option (#176)

README.md

@@ -44,6 +44,7 @@ There are some CMake options you might care about:
 | `ENABLE_IO_THREAD` | `ON` | When enabled, we start up a thread to do io processing, if disabled you should call `Discord_UpdateConnection` yourself.
 | `USE_STATIC_CRT` | `OFF` | (Windows) Enable to statically link the CRT, avoiding requiring users install the redistributable package. (The prebuilt binaries enable this option)
 | [`BUILD_SHARED_LIBS`](https://cmake.org/cmake/help/v3.7/variable/BUILD_SHARED_LIBS.html) | `OFF` | Build library as a DLL
+| `WARNINGS_AS_ERRORS` | `OFF` | When enabled, compiles with `-Werror` (on *nix platforms). |
 
 ## Continuous Builds
 

build.py

@@ -286,6 +286,8 @@ def libs(clean, static, shared, skip_formatter, just_release):
 
     if IS_BUILD_MACHINE:
         just_release = True
+        static_options['WARNINGS_AS_ERRORS'] = True
+        dynamic_options['WARNINGS_AS_ERRORS'] = True
 
     if PLATFORM == 'win':
         generator32 = 'Visual Studio 14 2015'

src/CMakeLists.txt

@@ -2,6 +2,7 @@ include_directories(${PROJECT_SOURCE_DIR}/include)
 
 option(ENABLE_IO_THREAD "Start up a separate I/O thread, otherwise I'd need to call an update function" ON)
 option(USE_STATIC_CRT "Use /MT[d] for dynamic library" OFF)
+option(WARNINGS_AS_ERRORS "When enabled, compiles with `-Werror` (on *nix platforms)." OFF)
 
 set(CMAKE_CXX_STANDARD 14)
 
@@ -76,7 +77,13 @@ if(UNIX)
         -Wall
         -Wextra
         -Wpedantic
-        -Werror
+    )
+
+    if (${WARNINGS_AS_ERRORS})
+      target_compile_options(discord-rpc PRIVATE -Werror)
+    endif (${WARNINGS_AS_ERRORS})
+
+    target_compile_options(discord-rpc PRIVATE
         -Wno-unknown-pragmas # pragma push thing doesn't work on clang
         -Wno-old-style-cast # it's fine
         -Wno-c++98-compat # that was almost 2 decades ago