cmake: Move compiler flag tests into aom_configure.cmake.

Make the flag tests more visible instead of hiding them in the cmake
include.

BUG=https://bugs.chromium.org/p/aomedia/issues/detail?id=76

Change-Id: I64cab909a08408d96b3c739e7dad3b231e2912fd

build/cmake/aom_configure.cmake

@@ -21,6 +21,35 @@ include("${AOM_ROOT}/build/cmake/targets/${AOM_TARGET}.cmake")
 include(FindGit)
 include(FindPerl)
 
+# Test compiler flags.
+if (MSVC)
+  add_compiler_flag_if_supported("/W3")
+  # Disable MSVC warnings that suggest making code non-portable.
+  add_compiler_flag_if_supported("/wd4996")
+  if (ENABLE_WERROR)
+    add_compiler_flag_if_supported("/WX")
+  endif ()
+else ()
+  add_compiler_flag_if_supported("-Wall")
+  add_compiler_flag_if_supported("-Wdeclaration-after-statement")
+  add_compiler_flag_if_supported("-Wdisabled-optimization")
+  add_compiler_flag_if_supported("-Wextra")
+  add_compiler_flag_if_supported("-Wfloat-conversion")
+  add_compiler_flag_if_supported("-Wimplicit-function-declaration")
+  add_compiler_flag_if_supported("-Wpointer-arith")
+  add_compiler_flag_if_supported("-Wshadow")
+  add_compiler_flag_if_supported("-Wsign-compare")
+  add_compiler_flag_if_supported("-Wtype-limits")
+  add_compiler_flag_if_supported("-Wuninitialized")
+  add_compiler_flag_if_supported("-Wunused")
+  add_compiler_flag_if_supported("-Wvla")
+  if (ENABLE_WERROR)
+    add_compiler_flag_if_supported("-Werror")
+  endif ()
+  # Flag(s) added here negate CMake defaults and produce build output similar
+  # to the existing configure/make build system.
+  add_compiler_flag_if_supported("-Wno-unused-function")
+endif ()
 
 # TODO(tomfinegan): consume trailing whitespace after configure_file() when
 # target platform check produces empty INLINE and RESTRICT values (aka empty

build/cmake/compiler_flags.cmake

@@ -56,33 +56,3 @@ function (add_compiler_flag_if_supported flag)
   add_c_flag_if_supported(${flag})
   add_cxx_flag_if_supported(${flag})
 endfunction ()
-
-# Set warning levels.
-if (MSVC)
-  add_compiler_flag_if_supported("/W3")
-  # Disable MSVC warnings that suggest making code non-portable.
-  add_compiler_flag_if_supported("/wd4996")
-  if (ENABLE_WERROR)
-    add_compiler_flag_if_supported("/WX")
-  endif ()
-else ()
-  add_compiler_flag_if_supported("-Wall")
-  add_compiler_flag_if_supported("-Wdeclaration-after-statement")
-  add_compiler_flag_if_supported("-Wdisabled-optimization")
-  add_compiler_flag_if_supported("-Wextra")
-  add_compiler_flag_if_supported("-Wfloat-conversion")
-  add_compiler_flag_if_supported("-Wimplicit-function-declaration")
-  add_compiler_flag_if_supported("-Wpointer-arith")
-  add_compiler_flag_if_supported("-Wshadow")
-  add_compiler_flag_if_supported("-Wsign-compare")
-  add_compiler_flag_if_supported("-Wtype-limits")
-  add_compiler_flag_if_supported("-Wuninitialized")
-  add_compiler_flag_if_supported("-Wunused")
-  add_compiler_flag_if_supported("-Wvla")
-  if (ENABLE_WERROR)
-    add_compiler_flag_if_supported("-Werror")
-  endif ()
-  # Flag(s) added here negate CMake defaults and produce build output similar
-  # to the existing configure/make build system.
-  add_compiler_flag_if_supported("-Wno-unused-function")
-endif ()