[PATCH v3] tools/configure: only require bcc/ld86/as86 when needed

[Doug Goldstein <cardoe@cardoe.com>]

bcc/ld86/as86 are necessary when we build ROMBIOS. However if we do not
build it (and are not building qemu-trad), the build requirements are
overly strict and can lead to failures.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>

* note: autogen.sh must be rerun when commiting this *

change since v2:
- fixed up commit message per Konrad's suggestion
change since v1:
- fixed whitespace mess up on my part
---
 README             |  3 ++-
 tools/configure.ac | 11 +++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/README b/README
index dd36ec8..7cde45f 100644
--- a/README
+++ b/README
@@ -58,7 +58,6 @@ provided by your OS distributor:
     * iproute package (/sbin/ip)
     * GNU bison and GNU flex
     * GNU gettext
-    * 16-bit x86 assembler, loader and compiler (dev86 rpm or bin86 & bcc debs)
     * ACPI ASL compiler (iasl)
     * Libc multiarch package (e.g. libc6-dev-i386 / glibc-devel.i686).
       Required when building on a 64-bit platform to build
@@ -78,6 +77,8 @@ disabled at compile time:
       libnl-3-dev, etc).  Required if network buffering is desired
       when using Remus with libxl.  See docs/README.remus for detailed
       information.
+    * 16-bit x86 assembler, loader and compiler for qemu-traditional / rombios
+      (dev86 rpm or bin86 & bcc debs)
 
 Second, you need to acquire a suitable kernel for use in domain 0. If
 possible you should use a kernel provided by your OS distributor. If
diff --git a/tools/configure.ac b/tools/configure.ac
index 6c70040..5b5dda4 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -164,7 +164,13 @@ AC_ARG_ENABLE([rombios],
     ])
 ])
 AS_IF([test "x$enable_rombios" = "xyes"], [
-AC_DEFINE([HAVE_ROMBIOS], [1], [ROMBIOS enabled])
+    dnl as86, ld86, and bcc are only required when building rombios. They
+    dnl are only needed when the host system is x86 but that check is done
+    dnl for us above when checking if we should build with qemu-traditional.
+    AX_PATH_PROG_OR_FAIL([AS86], [as86])
+    AX_PATH_PROG_OR_FAIL([LD86], [ld86])
+    AX_PATH_PROG_OR_FAIL([BCC], [bcc])
+    AC_DEFINE([HAVE_ROMBIOS], [1], [ROMBIOS enabled])
     rombios=y],[
     rombios=n
 ])
@@ -320,9 +326,6 @@ dnl going to run, not the platform on which we are building (known as
 dnl "build" in gnu speak).
 case "$host_cpu" in
 i[[3456]]86|x86_64)
-    AX_PATH_PROG_OR_FAIL([AS86], [as86])
-    AX_PATH_PROG_OR_FAIL([LD86], [ld86])
-    AX_PATH_PROG_OR_FAIL([BCC], [bcc])
     AX_PATH_PROG_OR_FAIL([IASL], [iasl])
     ;;
 esac
-- 
2.4.10