Merge commit '7b06ddb8'

* commit '7b06ddb8':
  configure: use .altmacro for gnu as check on arm
Merged-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -4284,6 +4284,10 @@ if enabled asm; then
 \n: .int 0
 .endm
 m x
+EOF
+
+    check_as <<EOF || $nogas "GNU assembler not found, install gas-preprocessor"
+.altmacro
 EOF
 
     check_as <<EOF && enable as_func