Put platform detection in a single place.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7149dd..ef6ded3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -23,13 +23,25 @@
 endif()
 
 #--------------------------------------------------------------------
-# Set up GLFW for Win32 and WGL on Windows
+# Detect and select target platform
 #--------------------------------------------------------------------
 if (WIN32)
-    message(STATUS "Building GLFW for WGL on a Win32 system") 
-
-    # Define the platform identifier
     set(_GLFW_WIN32_WGL 1)
+    message(STATUS "Building GLFW for WGL on a Win32 system") 
+elseif (UNIX AND APPLE)
+    set(_GLFW_COCOA_NSGL 1)
+    message(STATUS "Building GLFW for X11 and GLX on a Unix-like system")
+elseif (UNIX AND NOT APPLE)
+    set(_GLFW_X11_GLX 1)
+    message(STATUS "Building GLFW for Cocoa and NSOpenGL on Mac OS X")
+else()
+    message(FATAL_ERROR "No supported platform was detected")
+endif()
+
+#--------------------------------------------------------------------
+# Set up GLFW for Win32 and WGL on Windows
+#--------------------------------------------------------------------
+if (_GLFW_WIN32_WGL)
 
     # Set up library and include paths
     list(APPEND glfw_INCLUDE_DIRS ${OPENGL_INCLUDE_DIR})
@@ -43,11 +55,7 @@
 #--------------------------------------------------------------------
 # Set up GLFW for Xlib and GLX on Unix-like systems with X Windows
 #--------------------------------------------------------------------
-if (UNIX AND NOT APPLE)
-    message(STATUS "Building GLFW for X11 and GLX on a Unix-like system")
-
-    # Define the platform identifier
-    set(_GLFW_X11_GLX 1)
+if (_GLFW_X11_GLX)
 
     find_package(X11 REQUIRED)
 
@@ -131,12 +139,8 @@
 #--------------------------------------------------------------------
 # Set up GLFW for Cocoa and NSOpenGL on Mac OS X
 #--------------------------------------------------------------------
-if (UNIX AND APPLE)
-    message(STATUS "Building GLFW for Cocoa and NSOpenGL on Mac OS X")
+if (_GLFW_COCOA_NSGL)
         
-    # Define the platform identifier
-    set(_GLFW_COCOA_NSGL 1)
-
     option(GLFW_BUILD_UNIVERSAL "Build GLFW as a Universal Binary" OFF)
 
     # Universal build
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 3f692cf..b8c0fd7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 
-if (UNIX)
+if (_GLFW_X11_GLX)
     configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libglfw.pc.cmake 
                    ${CMAKE_CURRENT_BINARY_DIR}/libglfw.pc @ONLY)
     install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libglfw.pc
@@ -30,24 +30,20 @@
                      x11_init.c x11_input.c x11_joystick.c
                      x11_keysym2unicode.c x11_opengl.c x11_time.c
                      x11_window.c)
-else()
-    message(FATAL_ERROR "No supported platform was selected")
 endif()
 
 add_library(glfw ${glfw_SOURCES})
 
 if (BUILD_SHARED_LIBS)
 
-    if (WIN32)
+    if (_GLFW_WIN32_WGL)
         # The GLFW DLL needs a special compile-time macro and import library name
         set_target_properties(glfw PROPERTIES 
                               COMPILE_DEFINITIONS "GLFW_BUILD_DLL;_GLFW_NO_DLOAD_GDI32;_GLFW_NO_DLOAD_WINMM"
                               PREFIX ""
                               IMPORT_PREFIX ""
                               IMPORT_SUFFIX "dll.lib")
-    endif()
-
-    if (APPLE)
+    elseif (_GLFW_COCOA_NSGL)
         # Append -fno-common to the compile flags to work around a bug in the Apple GCC
         get_target_property(glfw_CFLAGS glfw COMPILE_FLAGS)
         if (NOT glfw_CFLAGS)
@@ -59,7 +55,6 @@
 
     target_link_libraries(glfw ${glfw_LIBRARIES})
     target_link_libraries(glfw LINK_INTERFACE_LIBRARIES)
-
 endif()
 
 install(TARGETS glfw DESTINATION lib)