8244248: boot-jdk.m4 captures the version line using regex

Use awk instead of head

Reviewed-by: ihse, erikj

make/autoconf/boot-jdk.m4

@@ -74,7 +74,8 @@ AC_DEFUN([BOOTJDK_DO_CHECK],
           BOOT_JDK_FOUND=no
         else
           # Oh, this is looking good! We probably have found a proper JDK. Is it the correct version?
-          BOOT_JDK_VERSION=`"$BOOT_JDK/bin/java$EXE_SUFFIX" $USER_BOOT_JDK_OPTIONS -version 2>&1 | $HEAD -n 1`
+          # Additional [] needed to keep m4 from mangling shell constructs.
+          [ BOOT_JDK_VERSION=`"$BOOT_JDK/bin/java$EXE_SUFFIX" $USER_BOOT_JDK_OPTIONS -version 2>&1 | $AWK '/version \"[0-9\._\-a-zA-Z]+\"/{print $ 0; exit;}'` ]
           if [ [[ "$BOOT_JDK_VERSION" =~ "Picked up" ]] ]; then
             AC_MSG_NOTICE([You have _JAVA_OPTIONS or JAVA_TOOL_OPTIONS set. This can mess up the build. Please use --with-boot-jdk-jvmargs instead.])
             AC_MSG_NOTICE([Java reports: "$BOOT_JDK_VERSION".])
@@ -529,7 +530,8 @@ AC_DEFUN([BOOTJDK_CHECK_BUILD_JDK],
         BUILD_JDK_FOUND=no
       else
         # Oh, this is looking good! We probably have found a proper JDK. Is it the correct version?
-        BUILD_JDK_VERSION=`"$BUILD_JDK/bin/java" -version 2>&1 | $HEAD -n 1`
+        # Additional [] needed to keep m4 from mangling shell constructs.
+        [ BUILD_JDK_VERSION=`"$BUILD_JDK/bin/java" -version 2>&1 | $AWK '/version \"[0-9\._\-a-zA-Z]+\"/{print $ 0; exit;}'` ]
 
         # Extra M4 quote needed to protect [] in grep expression.
         [FOUND_CORRECT_VERSION=`echo $BUILD_JDK_VERSION | $EGREP "\"$VERSION_FEATURE([\.+-].*)?\""`]