make BUILD_TOXAV and option and fail if dependencies are missing

fixes #482

2 files changed, 10 insertions, 5 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7f49313..1f3d77ad 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -170,12 +170,17 @@ if(ASAN)
   set(CMAKE_REQUIRED_LIBRARIES "${SAFE_CMAKE_REQUIRED_LIBRARIES}")
 endif()
 
+option(BUILD_TOXAV "Whether to build the tox AV library" ON)
+
 include(Dependencies)
 
-if(OPUS_FOUND AND VPX_FOUND)
-  set(BUILD_TOXAV TRUE)
-else()
-  set(BUILD_TOXAV FALSE)
+if (BUILD_TOXAV)
+  if(NOT OPUS_FOUND)
+    message(SEND_ERROR "Option BUILD_TOXAV is enabled but required library OPUS was not found.")
+  endif()
+  if(NOT VPX_FOUND)
+    message(SEND_ERROR "Option BUILD_TOXAV is enabled but required library VPX was not found.")
+  endif()
 endif()
 
 ################################################################################
diff --git a/appveyor.yml b/appveyor.yml
index ec90e428..4b4bfb20 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -13,7 +13,7 @@ install:
 - cd ..
 
 before_build:
-- cmake . -DBOOTSTRAP_DAEMON=OFF -DENABLE_SHARED=OFF
+- cmake . -DBOOTSTRAP_DAEMON=OFF -DENABLE_SHARED=OFF -DBUILD_TOXAV=OFF
 
 build:
   project: INSTALL.vcxproj