cmake: Prevent glproc.py from being called multiple times simultaneously.

CMake generated Visual Studio project files seem to attach the custom
command to every project (target) that uses them.  glproc.cpp was being
used in two targets, and consequently glproc.py was being call multiple
times, often simultanouelsy, causing the build to abort (particularly on
AppVeyor.)

Putting the glproc.cpp in a single static library seems to avoid the
issue reliably.

1 files changed, 8 insertions, 11 deletions

diff --git a/dispatch/CMakeLists.txt b/dispatch/CMakeLists.txt
index d023e6e9..ddb38153 100644
--- a/dispatch/CMakeLists.txt
+++ b/dispatch/CMakeLists.txt
@@ -11,8 +11,9 @@ add_custom_command (
         ${CMAKE_CURRENT_SOURCE_DIR}/glproc.py
         ${CMAKE_CURRENT_BINARY_DIR}/glproc.hpp
         ${CMAKE_CURRENT_BINARY_DIR}/glproc.cpp
-    DEPENDS
+    MAIN_DEPENDENCY
         glproc.py
+    DEPENDS
         dispatch.py
         ${CMAKE_SOURCE_DIR}/specs/wglapi.py
         ${CMAKE_SOURCE_DIR}/specs/glxapi.py
@@ -24,28 +25,24 @@ add_custom_command (
 )
 
 
-# Wrap glproc.hpp as a target to prevent the command from being executed
-# multiple times simulatenously, when the targets that depend on it are built
-# in parallel.
-add_custom_target (glproc DEPENDS
+# Wrap glproc.{hpp,cpp} as a target to prevent the command from being executed
+# multiple times simultanously, when the targets that depend on it are built in
+# parallel.
+add_convenience_library (glproc EXCLUDE_FROM_ALL
     ${CMAKE_CURRENT_BINARY_DIR}/glproc.hpp
     ${CMAKE_CURRENT_BINARY_DIR}/glproc.cpp
 )
 
-
 add_convenience_library (glproc_gl EXCLUDE_FROM_ALL
     glproc_gl.cpp
-    ${CMAKE_CURRENT_BINARY_DIR}/glproc.cpp
 )
-
 add_dependencies (glproc_gl glproc)
+target_link_libraries (glproc_gl glproc)
 
 if (ENABLE_EGL)
     add_convenience_library (glproc_egl EXCLUDE_FROM_ALL
         glproc_egl.cpp
-        ${CMAKE_CURRENT_BINARY_DIR}/glproc.cpp
     )
-
     add_dependencies (glproc_egl glproc)
+    target_link_libraries (glproc_egl glproc)
 endif ()
-