Bug 646254 - configure should error out if yasm version is too low to assemble libjpeg-turbo. r=khuey

Will generate an error if yasm is not at least 1.1.0 unless --disable-libjepg-turbo is passed to configure.

configure.in

@@ -4971,6 +4971,7 @@ VPX_AS_CONVERSION=
 VPX_ASM_SUFFIX=
 VPX_X86_ASM=
 VPX_ARM_ASM=
+MOZ_LIBJPEG_TURBO=1
 LIBJPEG_TURBO_AS=
 LIBJPEG_TURBO_ASFLAGS=
 LIBJPEG_TURBO_X86_ASM=
@@ -6449,18 +6450,17 @@ dnl ========================================================
 dnl = libjpeg-turbo configuration
 dnl ========================================================
 
+MOZ_ARG_DISABLE_BOOL(libjpeg_turbo,
+[ --disable-libjpeg-turbo  Disable optimized jpeg decoding routines],
+    MOZ_LIBJPEG_TURBO=,
+    MOZ_LIBJPEG_TURBO=1)
+
 dnl Detect if we can use yasm to compile libjpeg-turbo's optimized assembly
 dnl files.
-AC_MSG_CHECKING([for YASM assembler])
-AC_CHECK_PROGS(LIBJPEG_TURBO_AS, yasm, "")
 
-dnl XXX jlebar -- need a yasm version check here.
+if test -n "$MOZ_LIBJPEG_TURBO"; then
 
-if test -n "LIBJPEG_TURBO_AS"; then
-
-  LIBJPEG_TURBO_AS="yasm"
-
-  dnl We have YASM; see if we support it on this platform.
+  dnl Do we support libjpeg-turbo on this platform?
   case "$OS_ARCH:$OS_TEST" in
   Linux:x86|Linux:i?86)
     LIBJPEG_TURBO_ASFLAGS="-f elf32 -rnasm -pnasm -DPIC -DELF"
@@ -6496,14 +6496,33 @@ if test -n "LIBJPEG_TURBO_AS"; then
   ;;
   esac
 
-fi # end have YASM
+fi
+
+dnl If we're on a system which supports libjpeg-turbo's asm routines and
+dnl --disable-libjpeg-turbo wasn't passed, check for yasm, and error out if it
+dnl doesn't exist or we have too old of a version.
+if test -n "$LIBJPEG_TURBO_X86_ASM" -o -n "$LIBJPEG_TURBO_X64_ASM" ; then
+    AC_MSG_CHECKING([for YASM assembler])
+    AC_CHECK_PROGS(LIBJPEG_TURBO_AS, yasm, "")
+
+    if test -z "$LIBJPEG_TURBO_AS" ; then
+        AC_MSG_ERROR([yasm is required to build with libjpeg-turbo's optimized JPEG decoding routines, but you do not appear to have yasm installed.  Either install it or configure with --disable-libjpeg-turbo to use the pure C JPEG decoder.  See https://developer.mozilla.org/en/YASM for more details.])
+    fi
+
+    dnl Check for yasm 1.1 or greater.
+    if test "$_YASM_MAJOR_VERSION" -lt "1" -o \( "$_YASM_MAJOR_VERSION" -eq "1" -a "$_YASM_MINOR_VERSION" -lt "1" \) ; then
+        AC_MSG_ERROR([yasm 1.1 or greater is required to build with libjpeg-turbo's optimized JPEG decoding routines, but you appear to have version $_YASM_MAJOR_VERSION.$_YASM_MINOR_VERSION.  Upgrade to the newest version or configure with --disable-libjpeg-turbo to use the pure C JPEG decoder.  See https://developer.mozilla.org/en/YASM for more details.])
+    fi
+fi
 
 if test -n "$LIBJPEG_TURBO_X86_ASM"; then
-  AC_DEFINE(LIBJPEG_TURBO_X86_ASM)
+    AC_DEFINE(LIBJPEG_TURBO_X86_ASM)
 elif test -n "$LIBJPEG_TURBO_X64_ASM"; then
-  AC_DEFINE(LIBJPEG_TURBO_X64_ASM)
-else
-  AC_MSG_WARN([No assembler or assembly support for libjpeg-turbo.  Using unoptimized C routines.])
+    AC_DEFINE(LIBJPEG_TURBO_X64_ASM)
+elif test -n "$MOZ_LIBJPEG_TURBO"; then
+    dnl Warn if we're not building the optimized routines, even though the user
+    dnl didn't specify --disable-libjpeg-turbo.
+    AC_MSG_WARN([No assembler or assembly support for libjpeg-turbo.  Using unoptimized C routines.])
 fi
 
 dnl ========================================================