[AD] Patch for Cmake profiling build with gcc

[Edgar <edgarreynaldo@xxxxxxxxxx>]

Attached is a patch to fix the profiling build for allegro with gcc. It 
currently fails with undefined references to mcount. I added in 
CMAKE_SHARED_LINKER_FLAGS_PROFILE to '-pg' in the profiiling section and 
added that flag to the 'mark_as_advanced' field just below. I don't know 
what the 'mark_as_advanced' field does but that follows the same pattern 
as the other flags. With the patch it now correctly builds on Windows. 
Untested on other platforms but -pg should work with gcc everywhere.
--- CMakeLists.txt	2014-05-18 17:13:27.564607500 -0500
+++ CMakeLists.txt.new	2014-05-18 17:08:58.002759000 -0500
@@ -400,10 +400,13 @@
         CACHE STRING "profiling flags")
     set(CMAKE_EXE_LINKER_FLAGS_PROFILE "-pg"
         CACHE STRING "profiling flags")
+    set(CMAKE_SHARED_LINKER_FLAGS_PROFILE "-pg"
+        CACHE STRING "profiling flags")
     mark_as_advanced(
         CMAKE_C_FLAGS_PROFILE
         CMAKE_CXX_FLAGS_PROFILE
         CMAKE_EXE_LINKER_FLAGS_PROFILE
+        CMAKE_SHARED_LINKER_FLAGS_PROFILE
         )
 endif(COMPILER_GCC_OR_CLANG)