Special-case builtins in gen_spirv.bash

Apply the change of fc83fc7 ("updated built-in variable names to match
LLVM for SPIR-V documentation (issue intel#89)", 2016-03-14) to the script
generating `SPIRVNameMapEnum.h`, such that the output of the script
for builtins is aligned with the current code.

llvm-spirv/tools/spirv-tool/gen_spirv.bash

@@ -15,7 +15,11 @@ prefix=$1
 echo "template <> inline void SPIRVMap<$prefix, std::string>::init() {"
 
 cat $spirvHeader | sed -n -e "/^ *${prefix}[^a-z]/s:^ *${prefix}\([^= ][^= ]*\)[= ][= ]*\([0x]*[0-9][0-9]*\).*:\1 \2:p"  | while read a b; do
-  printf "  add(${prefix}%s, \"%s\");\n" $a $a
+  stringRep="$a"
+  if [[ $prefix == "BuiltIn" ]]; then
+    stringRep="BuiltIn$a"
+  fi
+  printf "  add(${prefix}%s, \"%s\");\n" "$a" "$stringRep"
 done
 
 echo "}